Where will it rain this weekend (Sep 26 - Sep 27)?
Short Answer
Rain is expected in Boston this weekend, September 26-27, 2026, with the market pricing this outcome at 94.0%.
1. Market Behavior & Drivers
The market's primary price driver was news of a potential nor'easter. On September 22, the contract surged 68.0 percentage points, from 6.0% to 74.0%, after multiple outlets reported a "rare September nor'easter" was expected to affect New York City during the resolution weekend. This single development accounted for the most significant price action in the market's history.
That gain fully reversed the next day. A price drop on September 23 is linked in reports to a FOX 13 Seattle forecast that called for drier conditions in western Washington. The contract fell to its current 15.0% probability. This lower price is more consistent with broader guidance from the NOAA/CPC, which forecasts above-normal precipitation probabilities for the Southwest and Lower Four Corners, not the Northeast. Correspondingly, contracts for rain in Atlanta, Austin, and Boston show 0¢ bids.
- Boston and Trenton show high rain probability, driven by GFS model forecasts.
- NOAA indicates slight heavy precipitation risk for the Southwest and Four Corners.
Who Wins and Why
| Outcome | Market | Model | Why |
|---|---|---|---|
| Newark | 78.0% | 75.0% | Meteorological analysis shows a strong probability of rain this weekend. |
| Miami | 60.0% | 60.0% | Current weather projections indicate some chance of weekend precipitation. |
| New York City | 81.0% | 80.8% | Forecasts indicate a high likelihood of rain over the weekend. |
| Trenton | 88.0% | 85.0% | Significant precipitation is expected based on current weather data. |
| West Palm Beach | 59.0% | 59.0% | Weather data suggests a notable possibility of rain this weekend. |
Current Context
The prediction market shows no current rain bids for key cities. The Robinhood market, titled "Where will it rain this weekend (Sep 26–Sep 27)," resolves from The Weather Company’s precipitation data [1]. Contracts for Atlanta, Austin, and Boston currently display 0¢. Trace precipitation and missing daily values count as 0 inches [1]. NOAA/CPC guidance for Sep 26–27, 2026 favors above-normal precipitation across the Southwest and Lower Four Corners, with probabilities exceeding 50% in portions of this region, linked to possible tropical-moisture advection [2]. The Eastern Seaboard, including the Southeast and parts of the Northeast, also favors above-normal precipitation due to frontal activity and potential surface-low development, marking the clearest wet-weather signal for the East [2]. Conversely, the Upper Mississippi Valley and western Great Lakes lean drier [3].
A secondary rain band extends to the Mid-Atlantic and Northeast. NOAA’s hazards outlook identifies elevated heavy-precipitation risk for Sep 25–Oct 1 in the lower Mid-Atlantic, Southeast, and Lower Mississippi Valley, with risk in the Southwest, southern Rockies, and Southern High Plains on Sep 25–26 [4]. Flooding is possible in parts of the Four Corners [4]. A deepening eastern-U.S. trough could produce cooler, drier conditions in parts of the Northeast, though exact placement remains uncertain [4]. The broader climate backdrop is a strengthening El Niño, expected to intensify and persist through February 2027 [5]. A Sep 22 global outlook assigned a 98% probability to a very strong event during October–December and a 75% probability of a record-breaking event [6]. This strong El Niño forcing may continue influencing the contiguous U.S. into October [7]. However, retrieved evidence does not establish a specific named storm or track affecting the United States on Sep 26–27; tropical influence remains a forecast uncertainty [8]. Expert guidance does not identify a meaningful low-elevation U.S. snow threat for this weekend [2].
Forecast confidence is regional, not precise city-level information. CPC reported above-average confidence for the earlier 6–10-day pattern due to model agreement, but also highlighted uncertainty in the evolving transitional pattern [2]. ECMWF advises interpreting ensemble spread as scenario uncertainty [9]. NWS/CPC products support using probabilistic precipitation and hazard guidance rather than a single deterministic map; CPC flags a slight heavy-precipitation risk for parts of the Southeast, Mid-Atlantic, and Northeast during Sep 23–27 [10]. NWS’s PQPF product provides low, expected, and high precipitation ranges by location [11]. While some long-range commercial pages provide location-specific signals, such as Weather25 showing an 8.2 mm precipitation forecast for the U.S. on Saturday, Sep 26, these are lower-authority and should not be treated as reliable city-level forecasts several days out [12]. NWS short-range QPF and local forecasts should become materially more useful during the final days before the weekend [2]. The available evidence supports a higher probability of measurable rain in the Southwest/Lower Four Corners and Southeast, with a meaningful but more track-sensitive risk from the Mid-Atlantic into the Northeast. It does not support precise city-level or rainfall-total pricing from this evidence alone [7].
Sources (12)
- 1September 26, 2026: Where will it rain this weekend (Sep 26 - Sep 27) Prediction Marketrobinhood.com
- 2Climate Prediction Center - 6-10 and 8-14 Day Prognostic Discussionscpc.ncep.noaa.gov
- 3Climate Prediction Center - 6-10 and 8-14 Day Prognostic Discussionscpc.ncep.noaa.gov
- 4Probabilistic Hazards Outlookcpc.ncep.noaa.gov
- 5El Niño set to become very strong, raising risks of extreme weather...wmo.int
- 6Global Seasonal Outlook (September 2026) - Worldreliefweb.int
- 7Climate Prediction Center - Week 3-4 Outlookcpc.ncep.noaa.gov
- 8Climate Prediction Center - Global Tropical Hazards Outlookcpc.ncep.noaa.gov
- 9Medium-range forecasts | ECMWFecmwf.int
- 10Probabilistic Hazards Outlookcpc.ncep.noaa.gov
- 11Probabilistic QPFweather.gov
- 12United States weather forecast for Saturday, 26 September 2026weather25.com
2. Price Chart
Historical Price (Probability)
Outcome probability
Date
3. Significant Price Movements
Notable price changes detected in the chart, along with research into what caused each movement.
Outcome: Seattle
📉 September 23, 2026: 36.0pp drop
Price decreased from 51.0% to 15.0%
What happened: The primary driver of the 36.0 percentage point drop was an updated traditional weather forecast indicating drier conditions for Seattle. A FOX 13 Seattle report, published around the time of the market movement on September 23, 2026, forecast Seattle and western Washington to turn drier for September 26–27, with a mix of clouds and sunshine [1]. This forecast directly contradicted the "rain in Seattle" outcome, leading to the sharp decline in market probability. No social media activity from key figures or viral narratives was identified in the provided research, rendering it irrelevant to this market movement.
Outcome: New York City
📈 September 22, 2026: 68.0pp spike
Price increased from 6.0% to 74.0%
What happened: The 68.0 percentage point price spike on September 22, 2026, was primarily driven by traditional news reports regarding a developing nor'easter expected to affect New York City that weekend [2][3][4][5]. On September 22, multiple outlets announced that a "rare September nor'easter" could bring significant rain, strong winds, and coastal flooding to NYC and the Northeast, increasing the perceived likelihood of rain [2][3][5]. While the market movement was described as a "news/social-media catalyst" in the query, the provided research did not identify specific social media activity or viral narratives correlating with the spike [6][7][8]. Social media was therefore largely irrelevant in this instance.
Outcome: West Palm Beach
📈 September 21, 2026: 20.0pp spike
Price increased from 0.0% to 20.0%
What happened: The 20.0 percentage point spike in West Palm Beach referenced on September 21, 2026, appears to be a misattribution; the provided research indicates this movement was for gasoline prices, not the "Where will it rain this weekend" prediction market outcome [9]. Gasoline prices in Palm Beach County surged, exceeding $4 per gallon, attributed to high crude prices and Middle East conflict [9]. Consequently, social media activity was irrelevant to a non-existent weather prediction market spike, with the observed price movement primarily driven by economic and geopolitical factors impacting the energy market [9].
Sources (9)
- 1Start of fall in Seattle bringing clouds, rain | FOX 13 Seattlefox13seattle.com
- 2NYC, NJ weather timeline: Here's when to expect impacts from developing nor'easter | FOX 5 New Yorkfox5ny.com
- 3Rare September nor’easter could bring coastal flooding, gusty winds to the Northeast - ABC17NEWSabc17news.com
- 4US Northeast Braces for Strong Storm Forecast to Hit on Fridayenergyconnects.com
- 5Potential Nor'easter Could Slam NYC With Rain, Wind, Flooding, Forecasters Say | Upper West Side, NY Patchpatch.com
- 6Will it rain in New York City on Sep 22, 2026? | Paritypredictparity.com
- 7Area Forecast Discussionweather.gov
- 8National Weather Serviceforecast.weather.gov
- 9Gasoline prices spike in Palm Beach County far past $4 per gallonpalmbeachpost.com
4. Market Data
Contract Snapshot
This market, titled "Where will it rain this weekend (Sep 26 - Sep 27)?", begins on Saturday, September 26, at 12:00 am EDT. The provided content does not explicitly detail the exact conditions that trigger a 'Yes' or 'No' resolution for rain in the specified cities (Miami, West Palm Beach, Oklahoma City). The maximum payout date for this market is listed as Sep 28, 2026.
Available Contracts
Market options and current pricing
| Outcome bucket | Yes (price) | No (price) | Last trade probability |
|---|---|---|---|
| Boston | $0.94 | $0.07 | 94% |
| Trenton | $0.92 | $0.18 | 88% |
| Philadelphia | $0.80 | $0.42 | 82% |
| New York City | $0.81 | $0.20 | 81% |
| Newark | $0.77 | $0.29 | 78% |
| Miami | $0.60 | $0.45 | 60% |
| West Palm Beach | $0.59 | $0.49 | 59% |
| Washington DC | $0.38 | $0.69 | 32% |
| Atlanta | $0.21 | $0.88 | 12% |
| Minneapolis | $0.81 | $0.39 | 77% |
| Oklahoma City | $0.49 | $0.66 | 53% |
| Chicago | $0.42 | $0.76 | 50% |
| Houston | $0.31 | $0.83 | 29% |
| New Orleans | $0.19 | $0.82 | 22% |
| San Antonio | $0.29 | $0.80 | 22% |
| Austin | $0.20 | $0.86 | 19% |
| Dallas | $0.13 | $0.88 | 15% |
| Denver | $0.50 | $0.88 | 36% |
| Phoenix | $0.57 | $0.73 | 24% |
| Seattle | $0.13 | $0.88 | 15% |
| San Francisco | $0.12 | $0.97 | 5% |
| Las Vegas | $0.08 | $0.99 | 3% |
| Los Angeles | $0.03 | $0.99 | 3% |
| College Station | $0.27 | $0.88 | 24% |
Market Discussion
For September 26–27, 2026, the strongest U.S. rain signal is identified across the Southeast, lower Mississippi Valley, and lower Mid-Atlantic, along with the Southwest, particularly eastern Arizona, New Mexico, and the Four Corners region [1][2][3][4]. In contrast, the Northeast, Great Lakes, and northern Mississippi Valley are comparatively less favored for widespread rain, and no broad low-elevation snow hazard is indicated [1][2][4][5][6][7]. Prediction market contracts for this period resolve based on daily precipitation exceeding 0 inches at official stations, with data verified by The Weather Company [8][9][10].
Sources (10)
- 1Probabilistic Hazards Outlookcpc.ncep.noaa.gov
- 2PMD from KWNCkamala.cod.edu
- 3Next Tropical Moisture Surge: Arizona Faces Heavy Rain and Flash Flooding Sep 24–26 - NewsBreaknewsbreak.com
- 4Climate Prediction Center - 6-10 and 8-14 Day Prognostic Discussionscpc.ncep.noaa.gov
- 5Climate Prediction Center - Week 3-4 Outlookcpc.ncep.noaa.gov
- 6Probabilistic Mountain Weather Forecastweather.gov
- 7Mountain Weatherweather.gov
- 8Where will it rain this weekend (Sep 26 - Sep 27)? Odds...kalshi.com
- 9Where will it rain this weekend (Sep 26 - Sep 27...predictmarketcap.com
- 10Where will it rain this weekend (Sep 26 - Sep 27)? - Kalshi noteringen | CoinRithmcoinrithm.com
5. Trust Index
Order book is critically thin.
Primary risk· Trade quality
How it adds up
Integrity80% of score77Good
Market integrity is low (63), but Integrity averages all three scores, so the other two pull it up. Only a critically low score would cap the total.
Trade quality20% of score49High Risk
Includes the cost to trade: a $10,000 order can't be filled here because the order book is too thin.
Trust score71Good
Weighted blend with hard caps — a critically weak safety pillar, or a severe trading anomaly, caps the total regardless of the rest. Full methodology · About the Trust Index
Trust profile
Integrity4 screens run · 6 don't apply
6. How do the weekend precipitation forecasts from the American GFS model compare to the European ECMWF model for key regions like the Northeast and the Southwest?
| Eastern Seaboard Precipitation Risk | GFS suggests stronger eastern-U.S. troughing; ECMWF implies lower onshore totals [1][2] |
|---|---|
| Southwest Precipitation Probability | Above-normal precipitation probabilities exceeding 50% across portions of the Southwest and Lower Four Corners (Sep 22–26 outlook) [1][2] |
| Northeast Precipitation Consensus | Interior portions and Great Lakes areas favored for near- to below-normal precipitation [1][2] |
For the weekend of September 26-27, 2026, American and European models diverge on Eastern Seaboard precipitation risks. The American GFS model forecasts stronger eastern-U.S. troughing, suggesting an increased heavy-precipitation risk over the coastal Gulf and Eastern Seaboard. Conversely, the European ECMWF model positions the mean frontal boundary further offshore, indicating lower onshore precipitation totals [1][2]. For the broader Northeast, the consensus points to a less uniformly wet weekend, with interior areas and regions near the Great Lakes expected to receive near- to below-normal precipitation [1][2].
The Southwest presents an uncertain but potentially wetter precipitation outlook than the Northeast. Probabilities for above-normal precipitation exceed 50% across portions of the Southwest and Lower Four Corners in the September 22–26 outlook [1][2]. This signal, however, is not definitive; rising heights could favor drier conditions over the Four Corners, while moisture advection linked to potential eastern-Pacific tropical activity remains a plausible factor for increased precipitation [1][2].
Forecasts should be interpreted probabilistically, lacking specific regional totals for precise comparisons. Public model-chart sources do not provide reliable numeric model-total comparisons by region for September 26–27 [3][4][5][6][7]. Therefore, claims about exact inch totals or city-level precipitation amounts would be overconfident, and model precipitation figures should be treated as probabilities rather than definitive measurements [3][4][5][6][7].
Sources (7)
- 1Probabilistic Hazards Outlookcpc.ncep.noaa.gov
- 2Climate Prediction Center - 6-10 and 8-14 Day Prognostic Discussionscpc.ncep.noaa.gov
- 3Model charts for USA (Significant Weather) | ECMWF IFS HRES 0z...weather.us
- 4WeatherBell Mapsmaps.weatherbell.com
- 5Index of /prob_precip_portal/co/ppp_co_66hr_2026092306ftp-wpc.ncep.noaa.gov
- 6Comparison of NCEP Stage IV precipitation composites with ECMWF modelecmwf.int
- 7AR-AFSv2: Enhancing Near-Real-Time Atmospheric River Forecasts for the 2025–2026 Winter Season in the US West Coastevents.ecmwf.int
7. What specific weather systems are forecast by NOAA to be the primary drivers of precipitation across the U.S. during the Sep 26-27 weekend?
| Primary Precipitation Drivers | Eastern U.S. trough, tropical moisture from eastern Pacific, Alaskan surface lows (Sep. 26-27 weekend) [1][2][3] |
|---|---|
| Eastern US Precipitation Affected | Southeast and Eastern Seaboard [1][2] |
| Western CONUS Precipitation Affected | Southwest and Lower Four Corners [1][2] |
NOAA's guidance indicates multiple systems will drive U.S. precipitation during the September 26-27 weekend, rather than a single named storm across the nation. The primary drivers are forecast to include an eastern U.S. trough, tropical moisture originating from the eastern Pacific, and multiple separate Alaskan surface lows [1][2][3]. The available guidance does not indicate a single named storm as the primary nationwide precipitation driver for this period [1][2][3].
Regionally, various systems will bring precipitation to specific parts of the U.S. The eastern U.S. trough and its associated frontal boundary are expected to cause precipitation in the Southeast and along the Eastern Seaboard, though its exact position carries some uncertainty [1][2]. For the western contiguous United States (CONUS), enhanced precipitation is favored from tropical moisture advecting northward from the eastern Pacific, impacting the Southwest and Lower Four Corners, with the National Hurricane Center monitoring potential developments off Mexico [1][2]. Alaska is expected to experience precipitation from multiple surface lows, and Hawaii is forecast to remain wet due to active tropical-Pacific convection [1].
A broad-scale pattern will also lead to comparatively drier conditions across central U.S. regions. A strong mid-level ridge is expected over south-central Canada and central North America, steering precipitation towards the western and eastern peripheral systems [1][3]. This pattern is forecast to result in drier conditions across parts of the Mississippi Valley, Midwest, Great Lakes, and Four Corners [1][3]. The NOAA Weather Prediction Center provides the operational short-range precipitation forecast for this target window, with valid periods starting at 12Z on Saturday, September 26, and Sunday, September 27; however, detailed named storm discussions were not exposed on search-accessible WPC pages for these dates [4][5][6].
Sources (6)
- 1Climate Prediction Center - 6-10 and 8-14 Day Prognostic Discussionscpc.ncep.noaa.gov
- 2Probabilistic Hazards Outlookcpc.ncep.noaa.gov
- 3Climate Prediction Center - Week 3-4 Outlookcpc.ncep.noaa.gov
- 4Weather Prediction Center (WPC) Home Page - NOAAnoaa.gov
- 5NCEP - Weather Prediction Center (WPC) Home Page - NOAAwpc.ncep.noaa.gov
- 6Probabilistic Precipitation Portalwpc.ncep.noaa.gov
8. What does the NOAA Climate Prediction Center's latest 8-14 day outlook indicate for precipitation probabilities across the U.S. covering the Sep 26-27 weekend?
| Relevant Outlook Period | September 26 October 2, 2026 (issued September 18, 2026) [1] |
|---|---|
| Key Wetter-than-Normal Regions | West, Upper Mississippi Valley, Southeast/coastal Carolinas, East Coast [2][3][4][5] |
| Confidence Level | Below average (2 out of 5) [4][5] |
NOAA's latest 8-14 day outlook predicts wetter-than-normal conditions in several regions. The NOAA Climate Prediction Center (CPC) has issued an 8-14 day outlook for the period of September 26 to October 2, 2026, which includes the September 26-27 weekend [2][1]. This outlook strongly favors above-normal precipitation for the West, Upper Mississippi Valley, Southeast, coastal Carolinas, and the broader East Coast [2][3][4][5]. Additionally, Alaska and Hawaii's eastern islands also show elevated probabilities for above-normal precipitation, with chances exceeding 50% for the eastern Hawaiian islands [4][5].
Conversely, specific areas anticipate drier conditions, with outlooks indicating probabilities. Areas around the Great Lakes, the Middle Mississippi Valley, the northern Mississippi Valley, the Tennessee Valley, and the interior Northeast are expected to experience relatively drier-than-normal conditions [2][3][4][6][5]. The CPC clarifies that these outlooks provide category probabilities for seven-day total precipitation, rather than daily forecasts, indicating enhanced categories that surpass the 33.33% climatological baseline [3][4].
Confidence in these 8-14 day patterns remains below average. The overall confidence in these 8-14 day patterns is assessed as below average, rated 2 out of 5 [4][5]. This lower confidence is primarily attributed to a complex western CONUS pattern and uncertainties regarding tropical influences [4][5].
Sources (6)
- 1NAEFS Experimental 8-14 Day Outlook - Climate Prediction Centercpc.ncep.noaa.gov
- 2Climate Prediction Center - 8 to 14 Day Outlookscpc.ncep.noaa.gov
- 3Climate Prediction Center - seasonal Outlookcpc.ncep.noaa.gov
- 4Climate Prediction Center - 6-10 and 8-14 Day Prognostic Discussionscpc.ncep.noaa.gov
- 5Climate Prediction Center - 6-10 and 8-14 Day Prognostic Discussionscpc.ncep.noaa.gov
- 6Climate Prediction Center - 6-10 and 8-14 Day Prognostic Discussionscpc.ncep.noaa.gov
9. What is the historical frequency of measurable precipitation in late September for key contract cities like Chicago, New York, and Denver?
| Chicago 2-day precipitation chance | About 51% [1] |
|---|---|
| New York City 2-day precipitation chance | About 45% [1] |
| Denver 2-day precipitation chance | About 34% [1] |
Chicago historically experiences the highest late September measurable precipitation among key contract cities, defined as at least 0.01 inches [2][1]. Historically, Chicago has roughly a 30% chance of measurable precipitation per day in late September, specifically around September 26-27 [1]. Over a two-day window, the chance of at least one measurable precipitation day in Chicago is approximately 51%, with a 29.9% chance specifically on September 26 [1][3]. Chicago O'Hare’s 1991–2020 normal precipitation total for both September 26 and September 27 is 0.10 inches [4].
New York City and Denver show lower late September precipitation probabilities. New York City historically has about a 26% chance of measurable precipitation per day in late September [1]. The chance of at least one measurable precipitation day over a two-day window is approximately 45% [1], with a 26% chance of a wet day (defined as at least 0.04 inches) throughout September [5]. The city's September mean precipitation is 4.31 inches [6]. Denver is the driest of the three cities for late September [7], with an approximate 19% chance of measurable precipitation per day [1]. The likelihood of at least one measurable precipitation day over a two-day window is about 34% [1], with a 19.1% chance for September 26 [8]. Denver’s 1991–2020 September precipitation normal is 1.35 inches, averaging 4.8 precipitation days for the month [9][7]. While historically uncommon at the end of September, measurable snowfall up to 5.9 inches on September 26 and 2.8 inches on September 27 is also possible [8].
Sources (9)
- 1I. Description - Daily Normalsncei.noaa.gov
- 2National Weather Serviceforecast.weather.gov
- 3Chicago (O'Hare) 1991-2020 Climate Normalsweather.gov
- 4September Normals for Temperature and Precipitation for Chicagoweather.gov
- 5New York City, Central Park September Weather, Average Temperature (New York, United States) - Weather Sparkweatherspark.com
- 6CENTRAL PARK NY SEPTEMBER ALMANACweather.gov
- 7Compare the Climate and Weather in Denver, Seattle, Chicago, and Newarkweatherspark.com
- 8NWS Boulder Denver Daily Normals and Records Septemberweather.gov
- 9New Monthly Climate Summary_Templateweather.gov
10. How do typical late-September rainfall patterns during a strong El Niño year compare for the West Coast versus the Southeast?
| El Niño Strength Probability (Sep-Nov 2026) | Greater than 90% chance of very strong El Niño [1][2][3] |
|---|---|
| Southeast Rainfall Forecast (Sep 26-27, 2026) | Clearer and more geographically extensive setup for organized or heavy rainfall [4][5] |
| West Coast Rainfall Forecast (Sep 26-27, 2026) | Conditional signal, concentrated in Southwest and southern California [4][6][7] |
Late-September 2026 forecast guidance indicated higher probability for organized heavy rainfall in the Southeast [4][5]. This was during a very strong El Niño event, projected to have over a 90% chance of being very strong from September through November and strengthening by September 10, 2026 [1][2][3]. While strong El Niño conditions typically lead to wetter outcomes for both the West Coast and the Gulf Coast/Southeast, these effects are usually most pronounced from October through March [8][9][10][11][12]. Consequently, typical strong-El Niño precipitation impacts are much less robust in late September, and areas like Southern California and parts of the Southwest frequently remain relatively dry as the summer monsoon concludes [13][14][15][10]. Climatologically, September is a comparatively wet period in the Southeast due to warm-season convection, whereas much of the West is typically dry [16].
Specific late-September forecasts favored the Southeast for organized rainfall. For the September 26-27, 2026, weekend, the West Coast rainfall signal was more conditional, concentrated primarily in the Southwest and southern California rather than across the entire coast [4][6][7]. The Climate Prediction Center's (CPC) September 17 week-2 hazards outlook noted a slight risk of heavy precipitation in the Southwest, southern Rockies, and Southern High Plains on September 25-26 [4]. In contrast, the immediate weekend forecast specifically favored the Southeast more for organized and heavy rainfall, driven by an eastern-U.S. trough, frontal activity, and potential Gulf surface-low development [4][5]. The CPC's outlook also identified a similar risk of heavy precipitation in the Southeast, lower Mississippi Valley, and lower Mid-Atlantic during September 25-October 1 [4]. West Coast rain was primarily concentrated in the Southwest and Four Corners, partly linked to tropical moisture [4][5]. The Southeast also benefits from an additional late-September rainfall pathway via tropical or subtropical systems; Florida's historical flood event frequency shows a secondary peak in September-October [17]. Contemporary 2026 seasonal guidance aligned with these expectations, strongly favoring above-normal precipitation across the Southeast and eastern Gulf Coast, with a weaker Western signal extending from southern California into the Southwest [18][19].
Sources (19)
- 1ENSO: Recent Evolution,cpc.ncep.noaa.gov
- 2Synopsis: ENSO-neutral conditions may transition to La Niña cocpc.ncep.noaa.gov
- 3Climate Prediction Center: ENSO Diagnostic Discussioncpc.ncep.noaa.gov
- 4Probabilistic Hazards Outlookcpc.ncep.noaa.gov
- 5Climate Prediction Center - 6-10 and 8-14 Day Prognostic Discussionscpc.ncep.noaa.gov
- 6PMD from KWNCkamala.cod.edu
- 7Climate Prediction Center - 6-10 and 8-14 Day Prognostic Discussionscpc.ncep.noaa.gov
- 8How does El Niño influence winter precipitation over the United States? | NOAA Climate.govprod-01-asg-www-climate.woc.noaa.gov
- 9United States El Niño Impacts | NOAA Climate.govclimate.gov
- 10El Niño and its Effect on the Southeast U.S. - National Weather Serviceweather.gov
- 11El Niño: A Historical Perspectivencei.noaa.gov
- 12Not what I ordered: How El Niño is like a bad bartender | NOAA Climate.govclimate.gov
- 13ATLAS No. 4 -- Abstractcpc.ncep.noaa.gov
- 14CPC: SPECIAL CLIMATE SUMMARY 97/2: EL NINO IMPLICATIONS FOR THE 1997 SOUTHWEST DROUGHT AND FALL/WINTER PRECIPITATIONcpc.ncep.noaa.gov
- 15El Niño and its Effect on the Southeast U.S.preview.weather.gov
- 161. Development of the US precipitation QC system and analysiscpc.ncep.noaa.gov
- 17Fall 2026 Climate Outlook for northeastern South Carolina and southeastern North Carolinaweather.gov
- 18Rare Strong PDO Negative El Niño Arrives - September 19, 2026econcurrents.substack.com
- 19Above-average rainfall forecast for the West as El Niño kicks into gearktla.com
11. What Could Change the Odds
Key Catalysts
The Robinhood prediction market, "Where will it rain this weekend (Sep 26 - Sep 27)" [1], will primarily react to official U.S. precipitation forecasts. NOAA/NWS indicates a slight risk of heavy precipitation on Sep 26 across parts of the Southwest, southern Rockies, and southern High Plains, with possible flooding in the Four Corners region [2][3]. A broader risk of heavy precipitation extends across portions of the lower Mid-Atlantic, Southeast, and Lower Mississippi Valley from Sep 25–Oct 1 [2][3]. The clearest signal for Sep 26–27 rainfall centers on the Southeast, lower Mid-Atlantic, and Lower Mississippi Valley, tied to frontal activity and potential surface-low development [2][4]. Conversely, areas like the Midwest, Great Lakes, and central Mississippi Valley show comparatively lower precipitation odds [4]. No meaningful U.S. snow catalyst is identified for the Sep 26–27 period [2][4].
Market participants should monitor model convergence and official forecast updates leading up to Sep 25 [1]. Precipitation for the event day, September 26, 2026, will be recorded under The Weather Company's rules, where trace precipitation and missing values count as 0 inches [1]. Market prices should be interpreted as implied probabilities, with settlement typically occurring within about one hour of event resolution [5]. NOAA/NWS products, including daily and hourly precipitation probabilities and quantitative precipitation forecasts, are the primary resolution sources for market settlement and location-specific decisions [6][7]. The Sep 25–26 window is a key period for precipitation risk in the Southwest/Four Corners and Southern Plains, while Sep 26–27 is most exposed to rainfall across the Southeast, Lower Mississippi Valley, and lower Mid-Atlantic [8][2].
Key Dates & Catalysts
- Expiration: September 30, 2026
- Closes: September 28, 2026
Sources (8)
- 1September 26, 2026: Where will it rain this weekend (Sep 26 - Sep 27) Prediction Marketrobinhood.com
- 2Probabilistic Hazards Outlookcpc.ncep.noaa.gov
- 3PMD from KWNCkamala.cod.edu
- 4Climate Prediction Center - 6-10 and 8-14 Day Prognostic Discussionscpc.ncep.noaa.gov
- 5Weather predictions | Polymarketpolymarket.com
- 6National Forecast Mapsweather.gov
- 7NOAA Graphical Forecast for Southeastgraphical.weather.gov
- 8Probabilistic Hazards Outlookcpc.ncep.noaa.gov
13. Historical Resolutions
Historical Resolutions: 20 markets in this series
Outcomes: 9 resolved YES, 11 resolved NO
Recent resolutions:
- KXRAINWKND-26SEP19-WPB: YES (Sep 21, 2026)
- KXRAINWKND-26SEP19-TTN: YES (Sep 21, 2026)
- KXRAINWKND-26SEP19-SFO: NO (Sep 21, 2026)
- KXRAINWKND-26SEP19-SEA: NO (Sep 21, 2026)
- KXRAINWKND-26SEP19-SATX: NO (Sep 21, 2026)
