Latest National Weather Service forecasts for Chicago's O'Hare Airport project a high temperature near 42°F on March 27, anchoring trader sentiment toward the 42-43°F (29%) and 40-41°F (26%) bins as the market's tight frontrunners. Ensemble models like GFS and ECMWF diverge slightly, with GFS leaning warmer at 43°F amid a weakening cold air mass and southerly winds, while ECMWF holds cooler around 41°F due to persistent mid-level clouds and lake-effect moderation from Lake Michigan. Diurnal heating potential differentiates these outcomes, as clearer skies could push into 42-43°F, but increased overcast risks capping at 40-41°F; historical late-March volatility adds uncertainty, with deviations of ±5°F common. Traders eye the 12Z model update for resolution shifts.
Experimental AI-generated summary referencing Polymarket data · UpdatedHighest temperature in Chicago on March 27?
Highest temperature in Chicago on March 27?
42-43°F 29%
40-41°F 26%
38-39°F 15%
44-45°F 11.6%
$16,488 Vol.
$16,488 Vol.
33°F or below
1%
34-35°F
2%
36-37°F
11%
38-39°F
15%
40-41°F
26%
42-43°F
29%
44-45°F
12%
46-47°F
8%
48-49°F
3%
50-51°F
2%
52°F or higher
4%
42-43°F 29%
40-41°F 26%
38-39°F 15%
44-45°F 11.6%
$16,488 Vol.
$16,488 Vol.
33°F or below
1%
34-35°F
2%
36-37°F
11%
38-39°F
15%
40-41°F
26%
42-43°F
29%
44-45°F
12%
46-47°F
8%
48-49°F
3%
50-51°F
2%
52°F or higher
4%
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 23, 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...Latest National Weather Service forecasts for Chicago's O'Hare Airport project a high temperature near 42°F on March 27, anchoring trader sentiment toward the 42-43°F (29%) and 40-41°F (26%) bins as the market's tight frontrunners. Ensemble models like GFS and ECMWF diverge slightly, with GFS leaning warmer at 43°F amid a weakening cold air mass and southerly winds, while ECMWF holds cooler around 41°F due to persistent mid-level clouds and lake-effect moderation from Lake Michigan. Diurnal heating potential differentiates these outcomes, as clearer skies could push into 42-43°F, but increased overcast risks capping at 40-41°F; historical late-March volatility adds uncertainty, with deviations of ±5°F common. Traders eye the 12Z model update for resolution shifts.
Experimental AI-generated summary referencing Polymarket data · Updated
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