The Chicago temperature market for May 17 predicts whether the city's high will reach or exceed 64°F. At 100% YES odds, traders are expressing near-complete certainty that tomorrow will meet or exceed this threshold. This level of confidence is reasonable given Chicago's late-May seasonal patterns — average highs in mid-May typically range from 68–72°F, well above the 64°F mark. The market is highly liquid ($5,915) despite the certainty, suggesting continuous intraday trading as weather forecasts refine. Resolution occurs at midnight UTC on May 17 using official National Weather Service data for Chicago's O'Hare International Airport. The 100% reading reflects the high baseline probability that any day in mid-May produces highs above 64°F; a cooler-than-expected system would be needed to flip the outcome. The odds trajectory shows the market already converged to certainty, indicating traders viewed tomorrow's warmth as near-inevitable.
What factors could move this market?
Chicago's weather on May 17 enters a critical seasonal transition period where winter cold snaps have become statistically rare but not impossible. The city's climate data shows that by mid-May, average daily highs stabilize around 68–72°F, with 64°F effectively representing a mild threshold rather than a significant barrier. Historically, Chicago experiences temperatures below 64°F on only 5–10% of days during mid-May, and this frequency declines sharply as the month progresses. The current 100% odds reflect this seasonal reality: achieving a high at or above 64°F on May 17 is the statistically dominant outcome under normal atmospheric conditions. Factors supporting the YES outcome dominate May 17's meteorological picture. The Northern Hemisphere enters its warm season with increasing solar radiation and longer daylight hours. Chicago's continental location means daytime heating readily pushes highs above 64°F unless a significant cold front moves through — a rare occurrence by mid-May. Typical synoptic patterns in May feature warming ridges and diminishing polar influence, all supporting above-normal temperatures. A NO outcome would require either an unexpected cold front or unusual atmospheric stalling that produces cloud cover and limited heating throughout the day. Chicago's recent weather history shows that true cold-snap days (highs near 50°F or below) occur perhaps 2–3 times per May across all 31 days. The 64°F threshold is roughly one standard deviation below May's mean, making outcomes significantly below this level statistically improbable. The 100% odds reading suggests traders have already fully priced in the seasonal reality: no further price movement is expected before resolution at midnight UTC. This convergence to certainty is typical in short-duration weather markets where resolution is imminent and underlying probabilities have stabilized. The high liquidity ($5,915 despite near-certainty) indicates active trading near edge cases — perhaps small wagers on the slim possibility of an unusual atmospheric event. Historical May temperature records confirm Chicago rarely sees daily highs below 60°F this late in spring, anchoring trader confidence in the outcome.
What are traders watching for?
Monitor National Weather Service Chicago office forecasts through May 17; unexpected cold front mention would shift market sentiment significantly.
Official high temperature recorded at O'Hare International Airport before midnight UTC May 17 resolves the market outcome.
Afternoon heating efficiency May 17 depends on cloud cover and wind patterns; sunny conditions favor YES significantly.
Rare mid-May cold systems require unusual jet stream patterns; track 500 mb geopotential height anomalies for intrusions.
How does this market resolve?
The market resolves YES if Chicago's official high temperature on May 17 reaches 64°F or higher, as recorded by the National Weather Service at O'Hare International Airport. Resolution occurs at midnight UTC on May 17 using verified weather service data.
Polymarket Trade is an independent third-party interface to the Polymarket CLOB prediction market exchange on Polygon — not affiliated with Polymarket, Inc. Prediction markets aggregate trader expectations into real-time probability estimates. Every market question resolves YES or NO based on a specific event outcome; traders buy shares of the side they believe will resolve positively. Prices range 0¢ (certain no) to 100¢ (certain yes) and naturally reflect the crowd-implied probability of YES. Polymarket Trade is non-custodial — your funds never leave your wallet. Open the full interactive page linked above to place orders, see order book depth, and execute a trade.
