Chicago in early May typically experiences spring warming, with average high temperatures in the mid-50s to low-60s Fahrenheit, a sharp contrast to winter's cold. A high of 35°F or below would represent a dramatic departure from seasonal norms and would require an unusual arctic air mass to penetrate the Midwest in late spring. Such an outcome would necessitate not just cold air aloft, but also weak upper-level winds that would allow that cold air to linger through the daytime hours. The 0% YES odds reflect trader confidence that such a deep freeze is virtually impossible this late in spring, when the warming trend becomes increasingly dominant. Weather patterns in early May generally favor continued warming as days lengthen and solar radiation increases. The last time Chicago experienced a hard freeze in early May was 1994, making such an event historically uncommon. Current atmospheric setup shows no indication of the upper-atmosphere trough and cold air source needed to produce such extreme cooling.
Deep dive — what moves this market
Chicago's climate transitions rapidly from spring to early summer during May, and the city's growing season typically kicks into high gear as temperatures stabilize above freezing. Historically, the last freeze of the season in Chicago occurs around mid-May on average, with late freezes becoming increasingly rare as the month progresses. By May 2nd, soil temperatures have often already warmed significantly, and warm-weather plants begin rapid growth. For a high temperature of 35°F or below to occur, an extremely strong polar vortex disruption and southward surge of arctic air would be required—a phenomenon that would represent a 1-in-50-year or rarer event at this time of year. Such events are typically preceded by visible atmospheric signatures: a deep upper-level trough extending far southward, a strong jet stream positioned over the region, and cold air aloft combined with nighttime radiational cooling. The Great Freeze of 1994 that affected Chicago occurred when a major arctic outbreak swept across the continent, but even then, May freezes are notable enough to be individually remembered. Current weather models show no indication of such a pattern developing through May 2nd. Tropical Atlantic sea surface temperatures are warmer than normal, contributing to a generally more active and warm-biased setup. The 0% market price reflects both historical rarity and the complete absence of atmospheric signals that would precede such an extreme cold snap. Even in scenarios with cloud breaks and light winds—conditions most favorable for nighttime cooling—daytime warming with lengthening days would still likely push highs well above freezing. Traders are pricing in the reality that while surprises can occur in weather, the confluence of factors needed for a 35°F high in early May is so unlikely that it commands essentially zero credence in the current forecast window.
What traders watch for
National Weather Service official high temperature report for Chicago released by 7 PM CDT on May 2, the definitive resolution metric
GFS and NAM forecast model consensus through May 1, particularly for any troughs or arctic air signatures in the upper atmosphere
May 2 cloud cover percentage and wind speed/direction, since clear skies and light winds maximize overnight cooling potential
May 1 overnight low temperature—any readings near or below freezing would indicate very cold air is present aloft
How does this market resolve?
The market resolves at 11:59 PM UTC on May 2, 2026, using the National Weather Service official daily high temperature for Chicago's official observation station.
Prediction markets aggregate trader expectations into real-time probability estimates. On Polymarket Trade, 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. This page summarizes the market state for readers arriving from search; for live trading (place orders, see order book depth, execute a trade) open the full interactive page linked above.
