This market has settled: RESOLVED
Settled on May 23, 2026
Will May 2026 be the 4th or lower hottest on record?
Will May 2026 be the 4th or lower hottest on record? Odds: 1.4% YES on Polymarket. See live prices and trade this market.
The market pricing May 2026 as having just over 1% chance of ranking 4th or lower (cooler) in historical records reflects overwhelming trader consensus that continued planetary warming makes a top-3 hottest May virtually certain. This matters as a real-time barometer of climate expectations heading into the critical 2026 summer season, with implications for agriculture, energy demand, and climate policy discussions.
Current Odds
| Platform | Yes | No | Volume | Trade |
|---|---|---|---|---|
| Polymarket | 1.1% | 98.9% | $98K | Trade on Polymarket |
Market Analysis
The bull case for YES (a cooler May 2026) rests on potential short-term climate variability that could temporarily suppress temperatures. A strong La Niña event developing through late 2025 and persisting into spring 2026 could create global cooling effects, as La Niña typically reduces worldwide temperature averages by 0.1-0.2°C. Additionally, an unexpected volcanic eruption releasing significant aerosols into the stratosphere before May 2026 could cause temporary cooling, similar to the Mount Pinatubo effect in 1991. The current nine consecutive months of record-breaking heat (as of late 2024) might statistically regress toward the mean, though this contradicts the long-term warming trend.
The bear case for NO (May 2026 ranks top-3 hottest) is supported by climate data showing accelerating warming trends. The last decade has seen May temperatures consistently rank among the hottest on record, with 2020, 2016, and 2023 holding the top positions. Current NOAA forecasts suggest ENSO-neutral or weak El Niño conditions heading into 2026, which historically correlate with elevated temperatures. The ongoing Arctic amplification effect and reduced ice albedo create persistent warming pressure. With atmospheric CO2 concentrations exceeding 420 ppm and continuing to rise, the baseline temperature keeps shifting upward, making it statistically improbable for any recent May to fall outside the top-3 rankings.
Key catalysts include NOAA’s ENSO outlook updates released monthly through early 2026, particularly the January and February 2026 forecasts that will clarify La Niña probability. The March-April 2026 global temperature anomaly data will provide crucial leading indicators for May’s trajectory. Traders should monitor volcanic activity globally, particularly in regions like Indonesia and the Pacific Ring of Fire. The final resolution depends on data from multiple temperature datasets (NASA GISS, NOAA, ERA5) typically published by mid-June 2026, comparing May 2026 against the historical record dating back to the 1880s.
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Frequently Asked Questions
Which temperature dataset will be used to determine if May 2026 ranks 4th or lower?
The market likely references major global datasets like NASA GISS, NOAA NCEI, or Copernicus ERA5. Traders should verify the specific resolution criteria, as different datasets occasionally show slight ranking variations due to methodology differences.
How much would a La Niña event need to cool global temperatures for May 2026 to rank outside the top 3?
A strong La Niña typically reduces global temperatures by 0.1-0.2°C, but given that recent Mays exceed historical averages by 1.0-1.5°C, even a robust La Niña would likely be insufficient without additional cooling factors like volcanic activity.
What was the last time a May ranked 4th or lower on the hottest record list?
This depends on when measurements are taken, but any May from roughly 2015 or earlier would have ranked 4th or lower at the time, before the 2016-2020-2023 surge pushed older records down the rankings.