On May 18, 2026, Chicago's meteorological day will close with a recorded high temperature that will either fall within the 62-63°F band or outside it. This hyper-specific weather market reflects trader conviction on an exceptionally narrow temperature range during late spring in the Midwest. The current 0% YES odds indicate that prediction market participants believe this tight 1-degree band is highly unlikely to be the day's peak temperature. Historically, Chicago's May climate produces highs between 70-80°F, making the 62-63°F range quite cool for mid-spring. The market is live now, allowing traders to position on whether conditions will materialize as unseasonably cool. Seasonal jet-stream positioning and cold-front timing will determine whether the outcome occurs. The prediction market will settle definitively based on the official National Weather Service high temperature reading recorded at Chicago's primary urban observation station on May 18.
What factors could move this market?
Chicago weather in May sits at a meteorological inflection point between spring and early summer, with synoptic patterns often marked by transitional variability. The 62-63°F range represents a notably cool scenario for mid-May, roughly 10-15 degrees below the typical climatological high for this date. For this outcome to occur, Chicago would need to experience conditions far colder than seasonal normal, typically the result of a strong upper-level trough and cold-core low-pressure system pushing down from Canada, paired with persistent cloud cover that limits daytime heating. Historical precedent for such cool May days in Chicago does exist: May 2013 saw an extended cool spell, and May 1975 produced several days with highs in the low-60s range, though the probability of hitting this specific 1-degree window on a randomly selected May date remains quite low. The current 0% YES odds reflect trader belief that this narrow band is exceptionally improbable. Prediction market pricing suggests participants view this outcome as a statistical tail event, with conviction likely stemming from seasonal climatology: May 18 typically carries a historical mean high near 72°F in Chicago, and even below-normal days at this time of year rarely dip into the low-60s. A 1-degree band 10-15 degrees below climatological mean requires rare convergence of factors. What could theoretically push the market toward YES? An unusually deep springtime trough aloft, combined with a fast-moving cold front, could produce such conditions. Spring in the Midwest occasionally witnesses surprises from polar air masses. However, historical April and May patterns show Chicago rarely experiences cool spells this aggressive. A cold front could drop highs 20-30 degrees in a single day, but holding a narrow 62-63°F band is probabilistically far harder than simply being moderately cool. The market spread reflects both statistical rarity and the fact that even cool May days in Chicago (say, 65-70°F highs) would resolve this market as NO. National Weather Service temperature observations will provide the settlement data.
What are traders watching for?
National Weather Service official high temperature for Chicago on May 18 must fall within the 62-63°F band; tail-event outcome probability is exceptionally low
Upper-level jet stream positioning and mid-level trough depth in May will determine whether Chicago experiences cool anomaly or typical spring conditions
Cold-front arrival timing and intensity could push daytime temperatures down, though hitting this specific narrow band remains statistically improbable
Cloud cover persistence and overnight low temperatures preceding May 18 will influence cold-air establishment
How does this market resolve?
This prediction market resolves YES if the National Weather Service records a high temperature between 62-63°F in Chicago on May 18, 2026. The official observation from Chicago's primary NWS station will provide deterministic settlement data.
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