Trader consensus on Polymarket heavily favors a Chicago high of 64-65°F at 27.4% implied probability, driven by the latest NOAA GFS and ECMWF ensemble means clustering around 64°F for March 20, amid a building upper-level ridge fostering southerly winds and above-normal temperatures. Differentiating the close 62-63°F (18%) and 66-67°F (17.2%) contenders are model spreads: GFS perturbations lean cooler due to potential mid-level cloudiness, while ECMWF favors warmer peaks from stronger subsidence. Historical March 20 highs average 46°F (1901-2023 O'Hare data), but fading El Niño and jet stream dip support this mild anomaly; 00z updates tomorrow could refine boundary layer forecasts and sway odds further.
Experimental AI-generated summary referencing Polymarket data · UpdatedHighest temperature in Chicago on March 20?
Highest temperature in Chicago on March 20?
64-65°F 27.3%
66-67°F 17.9%
62-63°F 18%
60-61°F 13%
$88,280 Vol.
$88,280 Vol.
59°F or below
11%
60-61°F
13%
62-63°F
18%
64-65°F
27%
66-67°F
18%
68-69°F
6%
70-71°F
2%
72-73°F
1%
74-75°F
1%
76-77°F
1%
78°F or higher
1%
64-65°F 27.3%
66-67°F 17.9%
62-63°F 18%
60-61°F 13%
$88,280 Vol.
$88,280 Vol.
59°F or below
11%
60-61°F
13%
62-63°F
18%
64-65°F
27%
66-67°F
18%
68-69°F
6%
70-71°F
2%
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 on Polymarket heavily favors a Chicago high of 64-65°F at 27.4% implied probability, driven by the latest NOAA GFS and ECMWF ensemble means clustering around 64°F for March 20, amid a building upper-level ridge fostering southerly winds and above-normal temperatures. Differentiating the close 62-63°F (18%) and 66-67°F (17.2%) contenders are model spreads: GFS perturbations lean cooler due to potential mid-level cloudiness, while ECMWF favors warmer peaks from stronger subsidence. Historical March 20 highs average 46°F (1901-2023 O'Hare data), but fading El Niño and jet stream dip support this mild anomaly; 00z updates tomorrow could refine boundary layer forecasts and sway odds further.
Experimental AI-generated summary referencing Polymarket data · Updated
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