Chicago's weather on April 20, 2026 marks the middle of spring in the Midwest. At this time of year, daytime highs typically range from the mid-50s to low 60s Fahrenheit, though spring weather in Chicago can be highly variable and unpredictable from day to day. This market asks whether the day's highest temperature will be 55°F or below—a threshold that represents cool to cold spring conditions for the region. Current market odds at 81% YES reflect traders' collective assessment that cooler conditions are likely to dominate on this date. The 19% NO position suggests some belief that warmer air masses or an early warming trend could push temperatures above the 55°F threshold. Temperature measurements are official and fully resolvable via NOAA or National Weather Service records, making this an objective and verifiable market. The clear end date and unambiguous resolution criteria—comparing the day's highest recorded temperature directly against the 55°F threshold—ensure that this market will settle definitively once the day concludes and official temperature data are published. Traders assess both seasonal climatological patterns and current weather models when evaluating probability in temperature markets.