Short Answer

Both the model and the market expect the highest temperature in Boston on May 13, 2026, to be 64° or above, with no compelling evidence of mispricing.

1. Market Behavior & Drivers

This market has experienced a significant, high-volume price drop within a generally sideways and narrow trading range. The contract began trading at a 5.0% probability before a sharp decline to a low of 1.0% on May 12. This downward movement appears to be driven by weather forecasts published around that time. Reports from sources like The Boston Globe and WeatherShogun indicated a high temperature in the low 60s for the middle of the week, with a significant warm-up not expected until the following weekend. The market price dropping to a near-zero probability suggests traders interpreted this information as making the "YES" outcome highly unlikely. The price has since settled at 2.0%, showing minimal recovery.
The trading volume provides strong evidence for market conviction in the lower price range. The overwhelming majority of the total volume, over 2,300 contracts, was traded during the price collapse from 5.0% to 1.0%. This indicates a decisive move by traders to sell off contracts in response to the emerging weather data. The subsequent minor price increase to 2.0% occurred on zero volume, implying it does not reflect a change in market activity or sentiment. The 1.0% level, established on high volume, now acts as a key support point, while the initial 5.0% price serves as the recent high. Overall, the chart suggests a strong consensus that the conditions for a "YES" resolution will not be met, with sentiment turning sharply negative following mid-week temperature forecasts.
  • Most forecasts for May 13, 2026, predict highs around 61-62°F.
  • The historical May 13 average of 61.6°F aligns with current forecasts.
  • A significant warming trend may precede May 13, potentially reaching 70s-80s.
  • Spring 2026's neutral ENSO phase may bring warmer mid-May temperatures.
  • Historical May 13 temperatures have reached 70°F or above occasionally.

Current Context

No verifiable observed highest temperature for Boston on May 13, 2026, was found. The retrieved sources did not confirm any observed highest temperature for this specific date. The only May 13-specific temperature available was a forecast from WeatherShogun, which indicated a "Day 61°F" for Wednesday, May 13, 2026 [1].
Forecasts from early May indicated a warming trend for Boston. On May 11, 2026, The Boston Globe predicted Greater Boston highs in the low 60s for the Tuesday period, with expectations of a warm-up later in the week towards the weekend [2]. Further reporting from The Boston Globe on May 12, 2026, forecast temperatures rising to the mid-70s for Saturday and potentially more than 80 degrees for Sunday across Boston and New England [3].
Sources (3)
  1. 1Wednesday, May 13, 2026. Boston, MA - Weather Forecastweathershogun.com
  2. 2New England Tuesday forecast calls for increasing sunshinebostonglobe.com
  3. 3The weekend you’ve been waiting for is on the waybostonglobe.com

2. Price Chart

Historical Price (Probability)

Outcome probability
Date

3. Market Data

Contract Snapshot

This market resolves to YES if the maximum temperature recorded in Boston on May 13, 2026, is greater than 63°F, and to NO if it is 63°F or below. The official temperature will be verified solely by the National Weather Service's Climatological Report (Daily), with traders cautioned about potential nuances in preliminary NWS data. Trading for this market concludes at 11:59 PM local time on May 13, 2026, with expiration occurring after the data release, or by May 14, 2026, at 1:00 AM EDT.

Market Discussion

The predicted highest temperature in Boston on May 13, 2026, is 62°F (17°C) [1]. Federally regulated weather prediction markets allow participants to trade contracts based on specific outcomes like daily high temperatures, with settlement typically based on official reports such as those from the National Weather Service [2][3][4]. However, social media frequently spreads viral, inaccurate forecasts by cherry-picking extreme model runs, leading to misinformation and underscoring the importance of consulting official sources for reliable long-range predictions [5][6][7][8].

Sources (8)
  1. 1Weather information for Boston, MA, USgoogle.com
  2. 2kalshi.comhelp.kalshi.com
  3. 3bettingusa.com
  4. 4rotowire.com
  5. 5wkyc.com
  6. 6gardenprofessors.com
  7. 7kyuk.org
  8. 8youtube.com

4. What specific weather patterns in the week leading up to May 13, 2026, could cause a significant deviation from Boston's historical mid-May temperature averages?

Historical mid-May average temperature67°F [1][2]
Expected temperature May 10 (inland)near 80°F [3]
Expected temperature May 11 and 12 (without sea breeze)80s [3]
Boston's temperatures in the week leading up to May 13, 2026, are projected to significantly surpass historical mid-May averages of 67°F [1][2]. This deviation is primarily attributed to a specific atmospheric pattern: a high pressure system combined with southerly flow and dry, sunny conditions. This pattern is crucial because it is expected to block the typical cooling sea breeze, leading to considerably warmer conditions [3].
Early May’s cool conditions will transition to warmer temperatures. While early May 2026 is initially forecast to be cool and wet, with highs in the 50s-60s and rainy weekends, a significant warm-up is anticipated to begin the week before May 13 [3][4]. By May 9, Boston could experience temperatures in the mid-70s, accompanied by a mix of sun and clouds and a westerly flow following rain. Inland areas may reach near 80°F on May 10, while coastal regions could see low 70s under sunny skies [3].
The absence of a sea breeze is key to peak warmth. Should the moderating sea breeze be absent on May 11 and 12, Boston and areas to its west could experience temperatures in the 80s, influenced by a ridge of high pressure over the Northeast [3]. This particular pattern, characterized by high pressure, a southerly flow, and dry, sunny conditions, is critical as it actively prevents the sea breeze that typically helps moderate heat in coastal areas [3].
Sources (4)
  1. 1May Weather in Boston Massachusetts, United Statesweatherspark.com
  2. 2Boston MA Weather in Maycurrentresults.com
  3. 3A May weekend warm-up for New England provides a taste of summerbostonglobe.com
  4. 4May forecast maps show Boston begins cool and wet but warms laterbostonglobe.com

5. What has been the range and average of Boston's highest recorded temperatures on May 13 over the past two decades (2006-2025)?

Lowest Recorded Temperature52°F in 2016 [1]
Highest Recorded Temperature75°F in 2011 [2]
Temperature on May 13, 201256°F [3]
Data for Boston's May 13 highest temperatures is incomplete for the full period. The provided research does not contain sufficient data to determine the full range and average of Boston's highest recorded temperatures on May 13 for the entire 2006-2025 period, as specific data for all years between 2006-2008 and 2021-2025 are not included. However, based on the available historical data for several years within this timeframe, the range of highest temperatures on May 13 for Boston is 23°F, and the average is 61.6°F.
Specific daily high temperatures on May 13 vary across years. The individual highest temperatures recorded on May 13, with provided citations, include 69°F in 2009 [4], 63°F in 2010 [5], 75°F in 2011 [2], 56°F in 2012 [3], 55°F in 2013 [6], 60°F in 2014 [7], 72°F in 2015 [8], 52°F in 2016 [1], 54°F in 2018 [1], and 60°F in 2020 [7]. Among these specific records, the lowest temperature noted was 52°F in 2016 [1], and the highest was 75°F in 2011 [2].
Sources (8)
  1. 1robinhood.com
  2. 2robinhood.com
  3. 3robinhood.com
  4. 4weatherspark.com
  5. 5weatherspark.com
  6. 6currentresults.com
  7. 7extremeweatherwatch.com
  8. 8extremeweatherwatch.com

6. How do the long-range forecasts from the GFS and European (ECMWF) models compare for the Boston area for the week of May 11-15, 2026?

High Temperature62°F (17°C) for May 13, 2026 [1][2]
Typical May Temperature Range50°F to 68°F [3]
ConditionsCloudy on May 13, 2026 [1]
Specific forecasts for May 13, 2026, indicate a moderate temperature. For Boston on Wednesday, May 13, 2026, the projected high temperature is approximately 62°F (17°C) [1][2]. As of early May 13, 2026, UTC, current weather forecasts predict cloudy conditions for that specific date [1]. Historically, general weather patterns for Boston in May typically suggest temperatures ranging between 50°F and 68°F [3].
The research lacks specific GFS and ECMWF model long-range forecasts. It is important to note that the provided information does not include specific long-range forecasts from either the GFS or European (ECMWF) models, nor does it offer a comparison between them for the specified week.
Sources (3)
  1. 1Weather information for Boston, MA, USgoogle.com
  2. 2accuweather.com
  3. 3weather25.com

7. Which official data sources, such as NOAA's station at Logan Airport, will be considered definitive for resolving the highest temperature on May 13, 2026?

Official Data SourceNational Weather Service's (NWS) Climatological Report (Daily) for Boston (Logan Airport), MA [1]
Responsible Forecast OfficeNational Weather Service Boston/Norton, Massachusetts, forecast office [2]
Logan Airport Measurement Start Year1937 [3]
The National Weather Service issues Boston's official daily temperature report. The National Weather Service's (NWS) Climatological Report (Daily) for Boston (Logan Airport), MA, is the definitive official data source for determining the highest temperature in Boston on any given day, such as May 13, 2026. This specific NWS report provides the official and final value used for such resolutions [1].
The NWS Boston office monitors the region's weather conditions. The National Weather Service Boston/Norton, Massachusetts, forecast office holds the responsibility for monitoring weather conditions throughout southern New England, including the Boston area [2]. Temperature extremes for Boston have been systematically measured at Logan International Airport since 1937 [3].
Sources (3)
  1. 1kalshi.com
  2. 2wikipedia.orgen.wikipedia.org
  3. 3currentresults.com

8. How do long-range climate signals like the ENSO phase forecasted for Spring 2026 compare to historical years with notably warm or cool mid-Mays in Boston?

Spring 2026 ENSO ForecastNeutral through late spring [1][2][3]
El Ni description: A single data point for a table.61-62% by May-July 2026 [1][2][3]
Boston May 13 Record High87 description: Research findings for a single question.

The H2 subtitle for each Q1-Q5 section is the original sub-question text verbatim (already MECE/paraphrase-validated upstream in ``generate_research_questions``). We do not ask Gemini Flash to invent a "SEO-optimized" subtitle here ", which had a neutral ENSO phase according to historical lists [4][5]. More recent warm May 13 highs include 78 dataset: dataset-name license: license-name language: en-us

Spring 2026 anticipates a neutral ENSO, potentially bringing warmer mid-May temperatures. The forecast for Spring 2026 indicates a neutral ENSO phase through late spring, with a 61-62% chance of transitioning to El Niño [6][7]. This potential transition suggests above-average warmth for Boston in mid-May if it occurs [6][7].
Historically, Boston has experienced notable warmth on May 13. Boston's record high temperature for May 13 was 87 degrees [8]. More recently, May 13 has seen warm highs reach 78 degrees [8].
Sources (8)
  1. 1https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdfcpc.ncep.noaa.gov
  2. 2Climate Prediction Center: ENSO Diagnostic Discussioncpc.ncep.noaa.gov
  3. 3El Niño forecast, to impact New England weather, hurricane seasonbostonglobe.com
  4. 4Boston Weather in 1947extremeweatherwatch.com
  5. 5ENSO Index According to JMA SSTA (1868-2020) - COAPScoaps.fsu.edu
  6. 6Strongest El Niño on record may be coming in 2026bostonglobe.com
  7. 7ENSO Impacts by Statecpc.ncep.noaa.gov
  8. 8Boston Record High by Day of the Yearextremeweatherwatch.com

9. What Could Change the Odds

Key Catalysts

WeatherShogun predicts a high temperature of 61°F for Boston Logan on May 13, 2026 [1]. A long-range forecast from an airport site indicates 16.7°C (62°F) and partly cloudy conditions for Logan International Airport on May 13 [2]. The Boston Globe forecasts upper 60s°F for Greater Boston on Wednesday [3], while a general airport forecast suggests lower 60s°F highs on multiple days, including showers [4].
No observed data is yet available on Wunderground for May 12 or May 13, 2026, as it is still pending [5]. Separately, Polymarket is leading at 64-65°F for the highest temperature in NYC on May 13 at LaGuardia [6].

Key Dates & Catalysts

  • Strike Date: May 14, 2026
  • Expiration: May 20, 2026
  • Closes: May 14, 2026
Sources (6)
  1. 1Wednesday, May 13, 2026. Boston, MA - Weather Forecastweathershogun.com
  2. 2Logan International Airport (BOS) 15 Day Weather Forecast, Boston United Statesairportdistancecalculator.com
  3. 3New England forecast: Scattered sprinkles move in amid cloudsbostonglobe.com
  4. 4BOS - Boston Logan International Airport Current Weather and Airport Delay Conditionsflightstats.com
  5. 5Boston, MA Weather History | Weather Undergroundwunderground.com
  6. 6Highest temperature in NYC on May 13? Trading Odds & Predictions (May 13, 2026) | Polymarketpolymarket.com

11. Historical Resolutions

Historical Resolutions: 20 markets in this series

Outcomes: 3 resolved YES, 17 resolved NO

Recent resolutions:

  • KXHIGHTBOS-26MAY11-T67: NO (May 12, 2026)
  • KXHIGHTBOS-26MAY11-T60: NO (May 12, 2026)
  • KXHIGHTBOS-26MAY11-B66.5: NO (May 12, 2026)
  • KXHIGHTBOS-26MAY11-B64.5: NO (May 12, 2026)
  • KXHIGHTBOS-26MAY11-B62.5: YES (May 12, 2026)