Rain in Los Angeles in May 2026?
Short Answer
Both the model and the market expect rain in Los Angeles in May 2026 to be above 1 inch, with no compelling evidence of mispricing.
1. Market Behavior & Drivers
Based on the provided chart data, the prediction market for "Rain in Los Angeles in May 2026?" has shown significant early volatility against an overall upward trend. The market opened with a 1.0% probability, which quickly spiked to a high of 13.0% within the first few days of trading, as seen in the sample data point for May 3rd. This sharp increase represents the most significant price movement to date. Following this peak, the price has since corrected and appears to be consolidating around the current 8.0% level. The provided context, which outlines the historically dry and sunny long-term forecast for May in Los Angeles, does not explain this initial spike. The price surge was likely driven by early market dynamics, speculative trading, or a short-term weather model run not reflected in the general climate data.
The trading volume provides insight into market conviction during these price swings. A significant portion of the total volume was traded during the initial price spike, indicating that the move from low single digits to 12.0% on May 3rd was backed by a burst of activity. The periods of zero volume suggest illiquidity and a lack of new information or disagreement among traders. The early peak of 13.0% has established an initial resistance level, which the market failed to sustain. The current price of 8.0% may be forming a new support or consolidation zone. Overall, while the market sentiment has moved from a near-zero chance of rain to a more tangible, albeit still low, 8.0% probability, the price action reflects uncertainty as traders weigh historical climate data against the potential for short-term weather events.
- Long-range forecasts and historical data indicate low chance of May rain.
- Three inches of May rainfall in Los Angeles is historically extremely rare.
- Old Farmer's Almanac forecasts below-normal May 2026 rain for Southern California.
- Drought conditions are expected to persist in Southern California into May.
- Weather events significantly influence prediction market contract prices.
Current Context
May 2026 in Los Angeles anticipates warm, sunny, and historically dry conditions. The general forecast indicates comfortable to warm daytime temperatures, averaging around 23°C (73°F), with overnight lows between approximately 13°C (55°F) and 16°C (61°F) [1][2][3][4][5]. Daily high temperatures across Los Angeles are projected to range from 62°F to 82°F, with specific forecasts for Los Angeles International Airport showing highs between 62°F and 74°F, and West Los Angeles between 65°F and 77°F [3][4][5]. About nine hours of sunshine are expected per day [1]. The broader climate outlook for California suggests temperatures will be above average through mid-May [6][7]. Historically, May is a very dry month in Los Angeles, marking the transition to the dry summer season [8].
Forecasts predict minimal rainfall for Los Angeles during May 2026. For May 2026, forecasts suggest approximately one to three days with some rainfall, with an average monthly rainfall of around 5mm (0.2 inches) [1][2][8]. The Old Farmer's Almanac predicts isolated showers between May 10-13 and May 14-19 [7][9]. AccuWeather's 11-day forecast from May 6th, 2026, indicates a 5% to 10% chance of rain around May 12th and 13th [10]. The Climate Prediction Center anticipates above-average temperatures for California through mid-May [6]. While a relatively active weather pattern could persist into early May, overall less precipitation is expected, though "lesser precipitation events are scattered across most model ensemble members right into early May" [11]. Specific dates with a low chance of rain include May 7th, 8th, 9th, 12th, 13th, and 15th according to some daily forecasts [10].
Prediction markets indicate minimal rain, while broader climate actions proceed. A climate prediction market for rain in Los Angeles in May 2026 shows very low expectations for significant rainfall, with contracts for "Above 1 inch," "Above 2 inches," and "Above 3 inches" all at 0 cents as of May 1st, 2026 [12]. In April 2026, Mayor Karen Bass released a Climate Action Plan for Los Angeles, aiming for carbon neutrality by 2045 [13][14][15]. Key goals include increasing renewable energy to 80% by 2030 and 100% by 2035, doubling local solar power by 2030, converting city buses to electric by 2028, and significantly increasing the city's local water sourcing to 70% by 2035 [13][14][15]. The plan also addresses reducing emissions at the Port of Los Angeles and LAX, increasing building energy efficiency, and expanding green spaces to combat extreme heat [13][14]. Furthermore, California as a state continues to lead in environmental regulation, with ongoing developments in climate regulation and reporting, mobile source regulation, and extended producer responsibility [16].
Sources (16)
- 1weather2travel.com
- 2weather25.com
- 3accuweather.com
- 4accuweather.com
- 5accuweather.com
- 6latimes.com
- 7almanac.com
- 8worldweatheronline.com
- 9almanac.com
- 10Weather information for Los Angeles, CA, USgoogle.com
- 11weatherwest.com
- 12robinhood.com
- 13latimes.com
- 14lacity.govmayor.lacity.gov
- 15lacity.govplan.mayor.lacity.gov
- 16bdlaw.com
2. Price Chart
Historical Price (Probability)
Outcome probability
Date
3. Market Data
Contract Snapshot
This market resolves to Yes if the total precipitation at CLILAX (Los Angeles Airport, CA) in May 2026 is strictly greater than 1 inch; otherwise, it resolves to No. The outcome is verified by the NWS Climatological Report for Los Angeles, which is the official and final data source for settlement. The market closes by May 31, 2026, at 11:59pm EDT, or earlier if the event occurs, with projected payouts 30 minutes after closing.
Market Discussion
May is historically one of the driest months in Los Angeles, with average precipitation typically ranging from 0.24 to 0.35 inches and an average 5.5% chance of rain [1][2][3]. Current long-range predictions for May 2026 indicate "below-normal rainfall" alongside "warmer than normal" temperatures, though some forecasts mention "isolated showers" or "very light" drizzle on specific days with minimal expected accumulation [4][5][6]. This expectation of little to no significant rain is reinforced by prediction market contracts for higher rainfall amounts in May 2026 being priced at zero [7].
4. What specific meteorological conditions, like a late-season atmospheric river, would need to occur in May 2026 to produce anomalous, multi-inch rainfall in Los Angeles?
| Required moisture flux anomaly | 3–5 standard deviations above normal [1] |
|---|---|
| Potential AR rainfall rate | 0.50–0.75 in/hr [1] |
| Rainiest May total historically (LA) | 3.57 inches (1921) [2] |
Anomalous multi-inch May rainfall requires specific late-season atmospheric river conditions. To produce anomalous, multi-inch rainfall in Los Angeles in May 2026, a late-season atmospheric river (AR) setup would be necessary, characterized by strong onshore winds, a sustained moisture corridor, and an anomalous moisture flux reaching approximately 3–5 standard deviations above normal [1]. Such an event would need to achieve AR magnitudes capable of generating rainfall rates of up to 0.50–0.75 inches per hour, resulting in multi-inch totals of 3–6 inches, given the correct forcing and moisture plume geometry [1]. An illustrative early May 2026 scenario for southern California describes a Level 2 (moderate) AR classification, with modeled totals ranging from 2–4 inches across coastal zones and higher elevations receiving double that amount [3].
Achieving multi-inch May rainfall would be historically significant. A multi-inch May event would necessitate a substantially deeper and stronger moisture and dynamic setup, contrasting with typical late-spring cut-off or instability patterns that often limit deep layered moisture [4]. Historically, Los Angeles' highest May rainfall on record is 3.57 inches, which occurred in 1921, indicating that an anomalous multi-inch outcome in May 2026 (e.g., exceeding approximately 3–4 inches) would represent a top-tier wet event for the month [2]. Attaining such a multi-inch monthly total would likely require either several above-normal rain days or a single AR-driven episode producing consecutive wet days, considering that even in early May, single-day rainfall records can surpass 1 inch [5].
Sources (5)
- 1WPC Met Watchwpc.ncep.noaa.gov
- 2Los Angeles May Precipitation Totalsextremeweatherwatch.com
- 3Atmospheric River Update: Southern California Braces for Record-Breaking Rainfall Surge - Climate Cosmosclimatecosmos.com
- 4Weather Synopsis – May 4, 2026 | Atmospheric and Oceanic Sciencesatmos.ucla.edu
- 5Record Rainfall by Day of Year for Downtown Los Angeles, Californialaalmanac.com
5. Based on NOAA's historical data for Downtown Los Angeles (USC), how many times since 1950 has May rainfall exceeded the market's 1-inch threshold?
| Data Availability for May Rainfall since 1950 | Not sufficiently available in provided sources [1] |
|---|---|
| May Record Single Day Rainfall (Downtown LA) | 2.02 inches on May 8, 1977 [2] |
| Confirmed May Rainfall Exceeding 1 Inch | May 1977 [1] |
The research was unable to fully determine how many times since 1950 May rainfall in Downtown Los Angeles (USC) exceeded the 1-inch threshold. This limitation arose because detailed year-by-year rainfall figures necessary for such an analysis were not directly accessible within the provided sources.
Specific climate summaries were identified, but detailed data remained inaccessible. For instance, the Western Regional Climate Center (WRCC) offers a "Period of Record Monthly Climate Summary" for the "LOS ANGELES DWTN USC CAMPUS, CALIFORNIA (045115)," spanning July 1, 1877, to June 9, 2016 [1][3]. While these sources indicated the existence of "Monthly Tabular data," these specific tables were not directly available for a comprehensive year-by-year examination [1][3].
However, one specific record confirmed that May 1977's rainfall surpassed the 1-inch mark. This was due to a "Record Single Day" rainfall event on May 8, 1977, which measured 2.02 inches [2]. This single event indicates that the total rainfall for May 1977 would have definitively exceeded the specified 1-inch threshold.
6. How do the May 2026 precipitation forecasts for Southern California from The Old Farmer's Almanac compare to the outlooks from the Climate Prediction Center (CPC)?
| Almanac May 2026 Rainfall Forecast | 0.2 inches (0.3 inches below average) [1] |
|---|---|
| Almanac April/May Outlook | Warmer than normal with below-normal rainfall [1] |
| CPC May 2026 Precipitation Expectation | Near historical average [2] |
The Old Farmer's Almanac predicts below-normal May 2026 rainfall for Southern California. It forecasts 0.2 inches of precipitation, which is 0.3 inches below the historical average for the region [1]. This aligns with their broader outlook for the Pacific Southwest, encompassing Southern California, which also anticipates a similar deficit [1]. Furthermore, the Almanac expects warmer than normal temperatures alongside the reduced rainfall for April and May, with southeastern California and the Pacific coast specifically projected to receive less than typical rainfall for May [1].
The CPC, conversely, expects Southern California's May precipitation to be near average. In contrast to the Almanac's forecast, the Climate Prediction Center (CPC) suggests Southern California will likely experience precipitation levels near its historical average during May 2026 [2]. While the CPC's "Week 3-4 Forecast Discussion" for mid-to-late May 2026 does mention a signal for a cutoff low near the coast, a weather feature that can bring rain [3], their broader summer precipitation outlook anticipates "near normal" precipitation across most of the country, indicating no significant deviation from average rainfall for Southern California [2].
7. Which specific NOAA weather station's data is the official source for Los Angeles rainfall, and what is the reporting procedure for finalizing monthly totals?
| NOAA Station Identifier | GHCND:USW00093134 [1] |
|---|---|
| Station Relocation Date | May 20, 2024 [2] |
| Station Elevation | 185 feet [3] |
Los Angeles rainfall data comes from a recently relocated NOAA station. The official NOAA weather station, identified as GHCND:USW00093134, underwent an official relocation on May 20, 2024 [2], [1]. Its observation site moved from the University of Southern California (USC) campus to the Frank Hotchkin Memorial Training Center in Elysian Park [2]. This station is specifically situated at 34.02°N latitude and 118.29°W longitude, at an elevation of 185 feet [3].
Monthly rainfall totals undergo rigorous collection and quality control. Daily precipitation measurements are initially gathered from Global Historical Climatology Network (GHCN-D) stations, collected by either volunteer observers or automated instruments [4]. These measurements are subsequently submitted to the National Centers for Environmental Information (NCEI) [4]. NCEI scientists perform quality checks to identify and remove systematic errors before calculating the final monthly totals. These finalized totals are then integrated into the NOAA Monthly U.S. Climate Gridded Dataset (NClimGrid) [4]. Additionally, the California Nevada River Forecast Center (CNRFC) compiles observed precipitation data, which includes monthly totals from National Weather Service cooperative observers [5].
8. What do the U.S. Seasonal Drought Outlook reports from the Climate Prediction Center indicate for Southern California leading into May 2026?
| Average May Rainfall | 0.3 inches (Los Angeles) [1][2] |
|---|---|
| Average May Rainy Days | 1 day (Los Angeles) [1][2] |
| Frequency of Heavy May Rain (0.5+ inches) | Once every five years (Los Angeles) [1] |
Drought conditions in Southern California are expected to persist into May. The U.S. Seasonal Drought Outlook indicates minimal change in the region's drought situation for May 2026, largely due to current snowmelt being considered sufficient to maintain reservoir and stream levels [3][4]. However, the winter wet season has concluded, and abnormal dryness is currently developing across the region [5]. Concerns exist regarding poor snow conditions in the Sierra Nevada mountains, which are crucial for California's water supply during the dry summer months, suggesting that a lack of continued moisture recharge beyond May could lead to a deterioration of conditions later in the season [3][4].
May historically marks the end of Southern California's wet season. For Los Angeles, May typically signals the transition from the rainy season into a dry summer period [6]. On average, Los Angeles receives approximately 0.3 inches of rain in May, with measurable rainfall occurring on about one day during the month [1][2]. Heavier rainfall events, defined as at least 0.5 inches, are uncommon, occurring only once every five years on average in May [1]. Although El Niño Southern Oscillation (ENSO) neutral conditions are anticipated through May, with a 61% probability of El Niño emerging between May and July 2026, its potential impact is not expected to bring significant precipitation during Southern California's traditionally dry month of May [5][7].
9. What Could Change the Odds
Key Catalysts
Prediction markets, which allow trading on binary event contracts, are significantly influenced by weather events, with the price of these contracts reflecting the market's collective probability assessment of a specific outcome [1][2]. Key catalysts that drive bullish or bearish sentiment in weather-related prediction markets include impacts on agriculture, where droughts, floods, or unseasonal freezes can drastically affect crop yields, leading to price fluctuations in agricultural commodities [3][4].
In the energy sector, extreme temperatures, such as cold snaps or heat waves, can significantly alter demand for heating oil, natural gas, and electricity, causing price volatility, and shifts in wind patterns can also affect renewable energy supply [3][5][4]. The insurance sector is directly impacted by the frequency and severity of major weather events, such as hurricanes, floods, or wildfires, which affect claims and can influence the stock prices of insurance companies [3]. Furthermore, weather conditions influence consumer behavior in retail, with prolonged pleasant weather boosting sales and severe weather deterring shoppers [3].
Accurate and timely weather data, including short-term alerts and longer-range monthly forecasts, are crucial for traders in these markets [3]. Updates to official forecasts or the emergence of more precise weather models can lead to instantaneous price adjustments in prediction markets [6][2]. Some analyses even suggest that prediction markets can, in certain instances, offer more accurate forecasts than traditional weather services due to the financial incentives for accuracy [6][7]. Prediction markets operate continuously, with prices adjusting in real-time as new information becomes available, until the contract's resolution date [2].
Key Dates & Catalysts
- Expiration: June 16, 2026
- Closes: June 01, 2026
11. Historical Resolutions
Historical Resolutions: 20 markets in this series
Outcomes: 2 resolved YES, 18 resolved NO
Recent resolutions:
- KXRAINLAXM-26APR-7: NO (May 01, 2026)
- KXRAINLAXM-26APR-6: NO (May 01, 2026)
- KXRAINLAXM-26APR-5: NO (May 01, 2026)
- KXRAINLAXM-26APR-4: NO (May 01, 2026)
- KXRAINLAXM-26APR-3: NO (May 01, 2026)
