Trader consensus overwhelmingly favors a Chicago high of 70-71°F on March 20, propelled by the latest NOAA and ECMWF ensemble forecasts converging on peaks in that narrow band amid a mild late-winter warm anomaly. National Weather Service guidance, drawing from GFS and Euro models initialized this week, projects southerly flow advecting 65-70°F air masses over Lake Michigan-influenced boundary layers, aligning with observed trends from O'Hare soundings showing 500mb ridges supportive of light warm advection. Historical March 20 highs average 45°F but have hit 70°F+ in 10% of recent analogs with similar setups. Realistic challenges include an accelerated cold frontal passage dropping highs sub-70°F or unexpected downslope föhn effects from the Rockies amplifying to 74°F+, though model spreads remain tight at ±2°F.
Experimental AI-generated summary referencing Polymarket data · UpdatedHighest temperature in Chicago on March 20?
Highest temperature in Chicago on March 20?
70-71°F 100.0%
72-73°F <1%
74-75°F <1%
76-77°F <1%
$255,245 Vol.
$255,245 Vol.
70-71°F
100%
72-73°F
<1%
74-75°F
<1%
76-77°F
<1%
78°F or higher
<1%
70-71°F 100.0%
72-73°F <1%
74-75°F <1%
76-77°F <1%
$255,245 Vol.
$255,245 Vol.
70-71°F
100%
72-73°F
<1%
74-75°F
<1%
76-77°F
<1%
78°F or higher
<1%
The resolution source for this market will be information from Wunderground, specifically the highest temperature recorded for all times on this day by the Forecast for the Chicago O'Hare Intl Airport Station once information is finalized, available here: https://www.wunderground.com/history/daily/us/il/chicago/KORD.
To toggle between Fahrenheit and Celsius, click the gear icon next to the search bar and switch the Temperature setting between °F and °C.
This market can not resolve to "Yes" until all data for this date has been finalized.
The resolution source for this market measures temperatures to whole degrees Fahrenheit (eg, 21°F). Thus, this is the level of precision that will be used when resolving the market.
Any revisions to temperatures recorded after data is finalized for this market's timeframe will not be considered for this market's resolution.
Market Opened: Mar 16, 2026, 6:02 AM ET
Resolution Source
https://www.wunderground.com/history/daily/us/il/chicago/KORDResolver
0x69c47De9D...Resolution Source
https://www.wunderground.com/history/daily/us/il/chicago/KORDResolver
0x69c47De9D...Trader consensus overwhelmingly favors a Chicago high of 70-71°F on March 20, propelled by the latest NOAA and ECMWF ensemble forecasts converging on peaks in that narrow band amid a mild late-winter warm anomaly. National Weather Service guidance, drawing from GFS and Euro models initialized this week, projects southerly flow advecting 65-70°F air masses over Lake Michigan-influenced boundary layers, aligning with observed trends from O'Hare soundings showing 500mb ridges supportive of light warm advection. Historical March 20 highs average 45°F but have hit 70°F+ in 10% of recent analogs with similar setups. Realistic challenges include an accelerated cold frontal passage dropping highs sub-70°F or unexpected downslope föhn effects from the Rockies amplifying to 74°F+, though model spreads remain tight at ±2°F.
Experimental AI-generated summary referencing Polymarket data · Updated
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