Chicago's May weather typically ranges from the mid-50s to mid-70s Fahrenheit, making the specific target of 64-65°F a relatively cool outcome for mid-month. This one-degree window is exceptionally narrow for a weather market, requiring precise alignment of atmospheric conditions to resolve YES. The 0% current odds suggest traders view this outcome as highly unlikely—a reflection of both the statistical improbability of hitting such a narrow band and the seasonal bias toward warming in May. The implied market pricing reflects consensus that Chicago's high will either exceed 65°F (the more probable outcome given typical spring warming) or fall below 64°F (unusual but less rare). With $6,096 in liquidity and minimal YES interest, this market attracts forecasters interested in precision weather outcomes and edge-case bets. The May 18 cutoff creates a specific, resolvable event: either the day's high temperature falls within the 64-65°F band or it doesn't, with no ambiguity. The current 0% price reflects strong market consensus about what traders expect Chicago's weather to deliver on that date.
What factors could move this market?
Chicago's spring climate exhibits characteristic volatility, with May temperatures historically spanning from occasional overnight frosts in early May to warm days in the 75-80°F range by late month. The specific 64-65°F target represents an unusually narrow band—just one degree—making it a precision bet rather than a broad directional wager. This market exemplifies how prediction markets can price extreme specificity; hitting a precise one-degree window requires the high to fall exactly in that band while all other daily highs fall outside it. The 0% YES odds reflect trader conviction that this outcome is sufficiently unlikely that the implied probability should approach zero. Factors that could drive toward the YES outcome (cooler outcome) include a late-spring cold front dipping south from Canada, nighttime lows in the 40s that limit overnight recovery, persistent cloud cover reducing solar heating, or an upper-level trough anchoring cooler air over the region. Such patterns occur occasionally in May but require specific synoptic alignment. Conversely, typical May patterns supporting warmth include the seasonal northward shift of the jet stream, increasing solar angle, and the gradual retreat of cool Arctic air. Chicago typically experiences warming from early May's average high of ~65°F toward late May's ~75°F. Historical records show May highs in Chicago range widely, but 64-65°F represents roughly the 20th percentile—cool for the season but not extreme. The nearest analog might be a cool, cloudy day following a frontal passage, which occurs occasionally. The zero odds and $6,096 liquidity suggest this market attracts both recreational traders seeking novelty and serious forecasters testing edge cases. The near-zero odds price in the high probability that Chicago's high will be either warmer (more common) or cooler (unusual but less rare than exactly 64-65°F) than the target band. Recent Midwest weather patterns show typical spring variability, with the jet stream oscillating between northern and southern positions. No extreme cold outbreak is currently forecast for May 18, and seasonal normals suggest warming should dominate.
What are traders watching for?
May 18 Chicago high must be exactly 64°F or 65°F; any deviation resolves NO in this narrow-band market.
Monitor 10-day forecasts from May 12 forward for unexpected cold fronts or systems that could cool the Midwest.
Chicago's typical May high averages 68-70°F; the 64-65°F target is ~5°F below seasonal normal, making YES statistically uncommon.
Current jet stream positioning favors spring warming; no polar outbreaks or significant cool patterns are forecast for May 18.
How does this market resolve?
Market resolves YES if Chicago's highest temperature on May 18, 2026 reaches between 64°F and 65°F inclusive. It resolves NO if the high is any other value.
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.
