Highest temperature in San Antonio on May 13, 2026?
Short Answer
Both the model and the market expect the highest temperature in San Antonio on May 13, 2026, to be between 91° and 92°, with no compelling evidence of mispricing.
1. Executive Verdict
- May 13, 2026, specific forecasts indicate highs of 89°F and 91°F.
- Severe D2-D4 drought conditions may amplify daily high temperatures.
- ENSO-neutral conditions likely point to above-average temperatures for the period.
- Recent May temperatures warmed significantly compared to 20th-century normals.
- Models predict San Antonio temperatures 3-4°F above average into May 2026.
Who Wins and Why
| Outcome | Market | Model | Why |
|---|---|---|---|
| 97° or above | 1.0% | 0.8% | Temperatures reaching 97° or above signal an exceptionally hot May day. |
| 89° to 90° | 37.0% | 33.3% | A high between 89° and 90° reflects a characteristic warm May temperature. |
| 93° to 94° | 12.0% | 13.9% | Highs ranging from 93° to 94° indicate a significantly warm mid-May forecast. |
| 91° to 92° | 39.0% | 40.0% | The forecast suggests a warm day with temperatures between 91° and 92°. |
| 88° or below | 12.0% | 9.0% | Temperatures at 88° or below point to a cooler than average May day. |
Current Context
San Antonio's forecast for May 13, 2026, predicts a high of 89°F. The highest temperature expected in San Antonio, Texas, on this date is 89°F (32°C) [^][^]. Conditions during the day are anticipated to be sunny with a 10% chance of rain. Overnight, the weather is expected to be partly cloudy, also with a 10% chance of rain. Humidity is forecasted to be around 60% [^].
Historically, May temperatures in San Antonio average 87°F. The average high temperature for May in San Antonio is 87°F [^]. For context on extreme conditions, the hottest May temperature ever recorded in San Antonio was 105°F. This extreme temperature occurred twice, most recently on May 29, 1927 [^].
2. Market Behavior & Price Dynamics
Historical Price (Probability)
Outcome probability
Date
This market has exhibited a sideways trading pattern, establishing a narrow range between 7% and 15%. The most significant price movement occurred early on when the price jumped from its starting point of 7% toward its peak of 15%. This initial rally appears to be a direct reaction to weather forecasts predicting a high of 89°F for the resolution date, which matches the threshold specified in the market's title. The current price of 12% represents a slight pullback from the highs but remains well above the initial price, suggesting the forecast is the primary driver of market activity.
Trading volume has been consistently low, with only 93 contracts traded in total. This low level of activity indicates a lack of strong conviction from traders and suggests that the market is relatively illiquid. The established price channel between 7% and 15% has created an apparent resistance level at 15% and an early support level at 7%. Market sentiment, as reflected by the current 12% price, implies that traders see a low probability of the high temperature reaching or exceeding 89°F. Despite the direct forecast, the market is pricing in considerable uncertainty, possibly factoring in the historical average high of 87°F or the inherent variability of weather predictions.
3. Market Data
Contract Snapshot
The market resolves to "Yes" if San Antonio's maximum temperature on May 13, 2026, is between 91-92°F, according to the National Weather Service's Climatological Report (Daily); otherwise, it resolves to "No" as the event is mutually exclusive. The last trading time is 11:59 PM local time on May 13, 2026. The market expires at the earliest of the first 7:00 or 8:00 AM ET after the May 13, 2026, data release, one week after May 13, 2026, or by May 14, 2026, 2:00 AM EDT. The official temperature data must come solely from the specified NWS Climatological Report, with caution advised for preliminary data.
Available Contracts
Market options and current pricing
| Outcome bucket | Yes (price) | No (price) | Last trade probability |
|---|---|---|---|
| 91° to 92° | $0.39 | $0.62 | 39% |
| 89° to 90° | $0.34 | $0.68 | 37% |
| 88° or below | $0.12 | $0.89 | 12% |
| 93° to 94° | $0.20 | $0.88 | 12% |
| 95° to 96° | $0.04 | $0.97 | 4% |
| 97° or above | $0.01 | $1.00 | 1% |
Market Discussion
Forecasts for May 13, 2026, largely predict a daily high temperature of 89°F [^][^][^][^], though one forecast suggests 91°F [^]. Conversely, a May 9, 2026, local news forecast mentioned more seasonal temperatures in the mid-80s around May 13th [^], while the National Weather Service anticipated highs returning to the 90s in the middle to late part of that week for the Austin/San Antonio area [^]. The San Antonio Express-News also reported on May 12, 2026, that southerly winds were expected to bring a warming trend and increased humidity later in the week [^].
4. How might the projected El Niño-Southern Oscillation (ENSO) cycle for Spring 2026 influence temperature patterns in San Antonio?
| ENSO-neutral probability | 80% from April to June [^] |
|---|---|
| El Niño development probability | 61% from May to July 2026 [^][^] |
| San Antonio above-average temp probability | 47% for Spring 2026 [^] |
ENSO-neutral conditions are widely projected for the upcoming spring. The projected El Niño-Southern Oscillation (ENSO) cycle for Spring 2026 primarily features an 80% chance of ENSO-neutral conditions from April to June [^]. This ENSO-neutral state is expected to contribute to a warm bias continuing into the spring season [^][^][^]. Concurrently, there is a 61% chance of El Niño developing between May and July 2026 [^][^].
Above-average temperatures are forecast for San Antonio this spring. Forecasting for this period suggests above-average temperatures for San Antonio [^]. The World Meteorological Organization (WMO) projects above-normal temperatures, particularly strong over southern North America, from May to July 2026 [^][^]. The NOAA outlook for Spring 2026 specifically favors above-average temperatures across Texas, with a 47% chance for San Antonio [^]. Additionally, models forecast San Antonio temperatures to be 3-4°F above average through May 10, 2026 [^].
5. How do recent May temperature trends (2015-2025) in San Antonio compare to the 20th-century climate normals for the city?
| San Antonio May Average High (1991-2020 Normal) | 86.6°F [^][^][^] |
|---|---|
| San Antonio May 90°F+ Days (2022) | 24 days [^] |
| San Antonio May 13, 2025 Record High | 103°F [^][^][^] |
San Antonio's May temperatures significantly warmed from 2015-2025 compared to 20th-century normals. Recent May temperature trends in San Antonio from 2015-2025 indicate significant warming when compared to the city's 20th-century climate normals. The 1991-2020 climate normals, serving as a proxy for 20th-century conditions, established an average May high of 86.6°F, an average low of 66.4°F, and a mean temperature of 76.5°F [^][^][^]. In contrast, recent May average highs have been distinctly hotter, with recorded values including 91°F in 2020, 95°F in 2022, 94°F in 2024, and 93°F in 2025 [^][^].
Increased frequency of hot days highlights San Antonio's accelerating extreme heat. This warming trend is further demonstrated by the increased frequency of hot days. Historically, early May typically experienced about 3-5 days reaching 90°F or higher [^]. However, recent years show a substantial rise in such occurrences during May, including 24 days in 2022, 22 days in 2018, and 18 days in 2020 [^]. More broadly, the number of triple-digit days annually in San Antonio has surged from an average of 9 between 1950-2004 to 26 over the past two decades [^]. A specific instance of this extreme heat occurred on May 13, 2025, when San Antonio registered a new record high of 103°F, surpassing the previous record of 98°F set in 1967 for that date [^][^][^]. This record was observed amidst a larger heat wave anticipating further 100°F+ temperatures [^][^][^].
6. Which long-range climate models, such as the CFSv2 and NMME, provide temperature anomaly forecasts for South Texas for May 2026?
| CFSv2 May 2026 Update | April 27, 2026 [^] |
|---|---|
| CFSv2 Initial Conditions | Late April to early May 2026 [^][^] |
| South Texas May 2026 Outlook | Warmer than normal [^] |
Long-range climate models offer May 2026 temperature anomaly forecasts for South Texas. The Climate Forecast System version 2 (CFSv2) and the North American Multi-Model Ensemble (NMME) are actively providing these predictions. The CFSv2 model, which produces monthly 2-meter temperature anomaly maps for North America, was most recently updated on April 27, 2026, incorporating initial conditions from late April to early May 2026 [^][^][^]. Similarly, the NMME provides one-month United States anomaly forecasts for May 2026, by integrating data from multiple distinct climate models and lead times [^].
Visualizations confirm a warmer-than-normal outlook for South Texas. Both CFSv2 and NMME temperature anomaly forecasts for May 2026, covering the continental United States and North America, are available for viewing through Tropical Tidbits [^][^][^]. Based on these model outputs, regional outlooks indicate that South Texas and the Rio Grande Valley are specifically projected to experience warmer than normal temperatures throughout May 2026 [^].
7. What are the initial seasonal outlooks from the NOAA Climate Prediction Center and ECMWF for Spring 2026 temperatures in the southern United States?
| CPC/ECMWF Outlook Scope | 1-month and 3-month periods (issued monthly) [^][^] |
|---|---|
| Forecast Type | Monthly or 3-month mean temperatures, not single-day forecasts [^][^] |
| Spring 2026 Southern U.S. Tercile Probabilities | Not retrievable from search results [^][^][^][^] |
Initial seasonal outlooks lack specific southern U.S. Spring 2026 temperature details. The NOAA Climate Prediction Center (CPC) and ECMWF do not provide specific southern U.S. temperature tercile probabilities for Spring 2026 (March, April, May) in the available information. While the CPC offers probability outlook maps for temperature deviations from normal for 1-month and 3-month periods, issued monthly, concrete southern U.S. tercile probability values for Spring 2026 were not retrievable [^][^]. Similarly, ECMWF's SEAS5 provides a "tercile summary" probability framework for mean 2-meter temperature anomalies over a selected 3-month period, but the actual southern U.S. tercile outcome values were not included from the map imagery in the search results [^][^].
Seasonal outlooks do not provide single-day temperature forecasts. These seasonal outlooks from NOAA CPC and ECMWF are not formatted to predict single-day temperatures for a specific prediction market question. Instead, both systems are designed for forecasting monthly or 3-month mean temperatures, rather than specific daily values [^][^]. Therefore, a prediction market question inquiring about the highest temperature in a specific city, such as San Antonio, on a particular day, like May 13, 2026, does not directly align with the format of either seasonal temperature outlook system [^][^].
8. What do long-term drought forecasts from the U.S. Drought Monitor indicate for South Texas leading into Spring 2026, and how could this affect daily highs?
| South Texas Drought Condition | D2-D4 through May 2026 [^][^][^][^] |
|---|---|
| Temperature Amplification due to Drought | 2-5°F due to reduced evaporative cooling [^] |
| San Antonio Spring Temperature Outlook | 85% chance of above-normal (3-4°F above average) for April-May [^] |
Severe drought conditions are expected to persist across South Texas into spring 2026. As of early 2026, South Texas is experiencing D2-D4 drought conditions, which are forecasted to continue through May [^][^][^][^]. While recent rainfall has brought some improvements to central and east Texas, the southern part of the state is anticipated to endure a prolonged period of dryness [^][^].
Persistent drought conditions are projected to significantly amplify daily high temperatures. Drier soils and lower humidity associated with the ongoing drought are expected to increase daily high temperatures by 2-5°F due to diminished evaporative cooling [^]. For San Antonio, the Climate Prediction Center's spring outlook indicates an 85% probability of above-normal temperatures, with models forecasting temperatures 3-4°F above average for April and May [^].
May 2026 forecasts indicate significantly warmer, drier conditions for South Texas. Specifically, projections for May 13, 2026, in San Antonio suggest daily highs ranging from 84-91°F [^][^]. These elevated temperatures are expected alongside low precipitation levels, ranging from 1-68%, as the region transitions into a warmer and drier pattern [^][^][^].
9. What Could Change the Odds
Key Catalysts
Significant catalysts for prediction markets include the legal victory by Kalshi in October 2024 against the CFTC, which allowed it to offer election prediction markets and led to a broader range of event contracts [^] [^] . This legal development was a major driver for the expansion of prediction markets in the U.S. [^][^]. Concurrently, monthly trading volume dramatically increased from $1.2 billion in early 2025 to over $20 billion in January 2026 [^]. Looking ahead to May 2026, DraftKings and FanDuel are further pushing into prediction markets as market makers, an opportunity seen as potentially boosting their stock [^].
Conversely, regulatory changes have acted as bearish catalysts, with the Australian Communications and Media Authority blocking access to Polymarket in August 2025 [^] . Additionally, New Zealand ruled prediction markets like Polymarket and Kalshi as prohibited under gambling acts in February 2026 [^]. Bullish and bearish sentiments are influenced by various factors, including economic indicators such as GDP growth rates and interest rate changes [^][^][^], political events like election results [^], news, social media [^][^][^], and even specific weather outcomes, for which prediction markets can be established [^]. Furthermore, policy shifts, such as banning insider trading and restricting participation, may reduce the accuracy of prediction markets by 15-40% over the next several years [^].
Key Dates & Catalysts
- Strike Date: May 14, 2026
- Expiration: May 20, 2026
- Closes: May 14, 2026
10. Decision-Flipping Events
- Trigger: Significant catalysts for prediction markets include the legal victory by Kalshi in October 2024 against the CFTC, which allowed it to offer election prediction markets and led to a broader range of event contracts [^] [^] .
- Trigger: This legal development was a major driver for the expansion of prediction markets in the U.S.
- Trigger: [^] [^] .
- Trigger: Concurrently, monthly trading volume dramatically increased from $1.2 billion in early 2025 to over $20 billion in January 2026 [^] .
12. Historical Resolutions
Historical Resolutions: 20 markets in this series
Outcomes: 3 resolved YES, 17 resolved NO
Recent resolutions:
- KXHIGHTSATX-26MAY11-T89: NO (May 12, 2026)
- KXHIGHTSATX-26MAY11-T82: NO (May 12, 2026)
- KXHIGHTSATX-26MAY11-B88.5: NO (May 12, 2026)
- KXHIGHTSATX-26MAY11-B86.5: NO (May 12, 2026)
- KXHIGHTSATX-26MAY11-B84.5: YES (May 12, 2026)
Get Real-Time Research Updates
Sign up for early access to live reports, historical data, and AI-powered market insights delivered to your inbox.
