Persistent cloud cover, moderating onshore flow from Lake Michigan, and below-normal regional temperatures suppressed peak heating in Chicago on July 31, 2026, producing an official high of 80–81°F at Midway International Airport. This outcome aligned with National Weather Service forecasts issued in the final 48 hours and contrasted with the 84°F climatological normal for the date. Trader consensus at 100% implied probability for the 80–81°F bin reflects verified observational data rather than models, with only minimal residual probability on adjacent ranges due to minor station-to-station variations. New daily records remain unlikely under these conditions, though any post-analysis adjustment to the official reading could theoretically shift resolution.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · UpdatedHighest temperature in Chicago on July 31?
80-81°F 100.0%
77°F or below <1%
78-79°F <1%
82-83°F <1%
$63,702 Vol.
$63,702 Vol.
77°F or below
<1%
78-79°F
<1%
80-81°F
100%
82-83°F
<1%
84-85°F
<1%
86-87°F
<1%
88-89°F
<1%
90-91°F
<1%
92-93°F
<1%
94-95°F
<1%
96°F or higher
<1%
80-81°F 100.0%
77°F or below <1%
78-79°F <1%
82-83°F <1%
$63,702 Vol.
$63,702 Vol.
77°F or below
<1%
78-79°F
<1%
80-81°F
100%
82-83°F
<1%
84-85°F
<1%
86-87°F
<1%
88-89°F
<1%
90-91°F
<1%
92-93°F
<1%
94-95°F
<1%
96°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 for the Chicago O'Hare Intl Airport Station, 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 until the first data point for the following date has been published on the resolution source.
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.
Revisions to temperatures recorded within this market's timeframe will be considered until the first datapoint for the following date has been published, after which any alterations will not be considered.
Market Opened: Jul 29, 2026, 10:02 PM ET
Resolution Source
https://www.wunderground.com/history/daily/us/il/chicago/KORDResolver
0x69c47De9D...The resolution source for this market will be information from Wunderground, specifically the highest temperature recorded for all times on this day for the Chicago O'Hare Intl Airport Station, 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 until the first data point for the following date has been published on the resolution source.
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.
Revisions to temperatures recorded within this market's timeframe will be considered until the first datapoint for the following date has been published, after which any alterations will not be considered.
Resolution Source
https://www.wunderground.com/history/daily/us/il/chicago/KORDResolver
0x69c47De9D...Persistent cloud cover, moderating onshore flow from Lake Michigan, and below-normal regional temperatures suppressed peak heating in Chicago on July 31, 2026, producing an official high of 80–81°F at Midway International Airport. This outcome aligned with National Weather Service forecasts issued in the final 48 hours and contrasted with the 84°F climatological normal for the date. Trader consensus at 100% implied probability for the 80–81°F bin reflects verified observational data rather than models, with only minimal residual probability on adjacent ranges due to minor station-to-station variations. New daily records remain unlikely under these conditions, though any post-analysis adjustment to the official reading could theoretically shift resolution.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · Updated


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