Official forecasts from the National Weather Service and supporting models project a daily maximum near 80°F for Chicago on August 21 under partly sunny to mostly cloudy skies with southwest winds of 5-10 mph. This consensus, moderated by Lake Michigan's thermal influence and limited daytime heating from increasing cloud cover, positions the 80-81°F range as the leading outcome. A 20-50% chance of late-day showers or thunderstorms could cap the peak slightly lower, supporting the secondary 78-79°F probability, while any clearing would allow modest warming into the low 80s. Recent model runs show minimal shifts, with historical late-August baselines near 82°F providing context for the slightly cooler outlook.
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 August 21?
Highest temperature in Chicago on August 21?
80-81°F 51%
78-79°F 28%
82-83°F 17%
76-77°F 4%
NEW
$12,489 Vol.
NEW
$12,489 Vol.
Aug 21, 2026
69°F or below
<1%
70-71°F
<1%
72-73°F
<1%
74-75°F
1%
76-77°F
4%
78-79°F
28%
80-81°F
51%
82-83°F
17%
84-85°F
4%
86-87°F
1%
88°F or higher
<1%
80-81°F 51%
78-79°F 28%
82-83°F 17%
76-77°F 4%
NEW
$12,489 Vol.
NEW
$12,489 Vol.
Aug 21, 2026
69°F or below
$272 Vol.
<1%
70-71°F
$258 Vol.
<1%
72-73°F
$282 Vol.
<1%
74-75°F
$687 Vol.
1%
76-77°F
$755 Vol.
4%
78-79°F
$1,893 Vol.
28%
80-81°F
$4,103 Vol.
51%
82-83°F
$2,119 Vol.
17%
84-85°F
$884 Vol.
4%
86-87°F
$939 Vol.
1%
88°F or higher
$297 Vol.
<1%
This market will resolve based on the highest temperature recorded in the 'Daily Observations' table on Weather Underground, not the figure displayed in the 'Day High & Low' summary section; in the event of any discrepancy between the two, the Daily Observations table shall be the primary resolution source not the Day High & Low section.
This market will resolve to the temperature range that contains the highest temperature recorded at the Chicago O'Hare Intl Airport Station in degrees Fahrenheit on 21 Aug '26.
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.Official forecasts from the National Weather Service and supporting models project a daily maximum near 80°F for Chicago on August 21 under partly sunny to mostly cloudy skies with southwest winds of 5-10 mph. This consensus, moderated by Lake Michigan's thermal influence and limited daytime heating from increasing cloud cover, positions the 80-81°F range as the leading outcome. A 20-50% chance of late-day showers or thunderstorms could cap the peak slightly lower, supporting the secondary 78-79°F probability, while any clearing would allow modest warming into the low 80s. Recent model runs show minimal shifts, with historical late-August baselines near 82°F providing context for the slightly cooler outlook.
This market will resolve based on the highest temperature recorded in the 'Daily Observations' table on Weather Underground, not the figure displayed in the 'Day High & Low' summary section; in the event of any discrepancy between the two, the Daily Observations table shall be the primary resolution source not the Day High & Low section.
This market will resolve to the temperature range that contains the highest temperature recorded at the Chicago O'Hare Intl Airport Station in degrees Fahrenheit on 21 Aug '26.
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.
This market will resolve to the temperature range that contains the highest temperature recorded at the Chicago O'Hare Intl Airport Station in degrees Fahrenheit on 21 Aug '26.
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: Aug 19, 2026, 9:56 PM ET
Volume
$12,489End Date
Aug 21, 2026Market Opened
Aug 19, 2026, 9:56 PM ETResolution Source
https://www.wunderground.com/history/daily/us/il/chicago/KORDResolver
0x69c47De9D...This market will resolve based on the highest temperature recorded in the 'Daily Observations' table on Weather Underground, not the figure displayed in the 'Day High & Low' summary section; in the event of any discrepancy between the two, the Daily Observations table shall be the primary resolution source not the Day High & Low section.
This market will resolve to the temperature range that contains the highest temperature recorded at the Chicago O'Hare Intl Airport Station in degrees Fahrenheit on 21 Aug '26.
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.Official forecasts from the National Weather Service and supporting models project a daily maximum near 80°F for Chicago on August 21 under partly sunny to mostly cloudy skies with southwest winds of 5-10 mph. This consensus, moderated by Lake Michigan's thermal influence and limited daytime heating from increasing cloud cover, positions the 80-81°F range as the leading outcome. A 20-50% chance of late-day showers or thunderstorms could cap the peak slightly lower, supporting the secondary 78-79°F probability, while any clearing would allow modest warming into the low 80s. Recent model runs show minimal shifts, with historical late-August baselines near 82°F providing context for the slightly cooler outlook.
This market will resolve based on the highest temperature recorded in the 'Daily Observations' table on Weather Underground, not the figure displayed in the 'Day High & Low' summary section; in the event of any discrepancy between the two, the Daily Observations table shall be the primary resolution source not the Day High & Low section.
This market will resolve to the temperature range that contains the highest temperature recorded at the Chicago O'Hare Intl Airport Station in degrees Fahrenheit on 21 Aug '26.
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.
This market will resolve to the temperature range that contains the highest temperature recorded at the Chicago O'Hare Intl Airport Station in degrees Fahrenheit on 21 Aug '26.
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.
Volume
$12,489End Date
Aug 21, 2026Market Opened
Aug 19, 2026, 9:56 PM ETResolution Source
https://www.wunderground.com/history/daily/us/il/chicago/KORDResolver
0x69c47De9D...Official forecasts from the National Weather Service and supporting models project a daily maximum near 80°F for Chicago on August 21 under partly sunny to mostly cloudy skies with southwest winds of 5-10 mph. This consensus, moderated by Lake Michigan's thermal influence and limited daytime heating from increasing cloud cover, positions the 80-81°F range as the leading outcome. A 20-50% chance of late-day showers or thunderstorms could cap the peak slightly lower, supporting the secondary 78-79°F probability, while any clearing would allow modest warming into the low 80s. Recent model runs show minimal shifts, with historical late-August baselines near 82°F providing context for the slightly cooler outlook.
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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