Official National Weather Service observations recorded a daily maximum of 78°F at Chicago-area stations on August 13, 2026, locking in the market's 100% implied probability for the 78–79°F bin. Pre-event guidance highlighted cloud cover, scattered showers, and a moderating lake breeze that suppressed insolation and kept highs several degrees below the 83°F climatological normal, with ensemble models showing only modest spread around the mid-to-upper 70s. These conditions aligned with historical analogs featuring comparable moisture and mid-level heights that rarely produce outliers beyond a narrow range. Realistic challenges would require unexpected clearing and stronger southerly flow to push peaks into the low 80s, though post-event data eliminated that possibility.
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 13?
Highest temperature in Chicago on August 13?
78-79°F 100.0%
67°F or below <1%
68-69°F <1%
70-71°F <1%
$73,375 Vol.
$73,375 Vol.
Aug 13, 2026
67°F or below
No
68-69°F
No
70-71°F
No
72-73°F
No
74-75°F
No
76-77°F
No
78-79°F
Yes
80-81°F
No
82-83°F
No
84-85°F
No
86°F or higher
No
78-79°F 100.0%
67°F or below <1%
68-69°F <1%
70-71°F <1%
$73,375 Vol.
$73,375 Vol.
Aug 13, 2026
67°F or below
$4,253 Vol.
No
68-69°F
$3,860 Vol.
No
70-71°F
$4,835 Vol.
No
72-73°F
$3,330 Vol.
No
74-75°F
$10,630 Vol.
No
76-77°F
$6,317 Vol.
No
78-79°F
$6,493 Vol.
Yes
80-81°F
$15,294 Vol.
No
82-83°F
$7,734 Vol.
No
84-85°F
$3,580 Vol.
No
86°F or higher
$7,050 Vol.
No
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 13 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 National Weather Service observations recorded a daily maximum of 78°F at Chicago-area stations on August 13, 2026, locking in the market's 100% implied probability for the 78–79°F bin. Pre-event guidance highlighted cloud cover, scattered showers, and a moderating lake breeze that suppressed insolation and kept highs several degrees below the 83°F climatological normal, with ensemble models showing only modest spread around the mid-to-upper 70s. These conditions aligned with historical analogs featuring comparable moisture and mid-level heights that rarely produce outliers beyond a narrow range. Realistic challenges would require unexpected clearing and stronger southerly flow to push peaks into the low 80s, though post-event data eliminated that possibility.
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 13 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 13 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 11, 2026, 9:02 PM ET
Volume
$73,375End Date
Aug 13, 2026Market Opened
Aug 11, 2026, 9:02 PM ETResolution Source
https://www.wunderground.com/history/daily/us/il/chicago/KORDResolver
0x69c47De9D...Outcome proposed: No
No dispute
Final outcome: No
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 13 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 National Weather Service observations recorded a daily maximum of 78°F at Chicago-area stations on August 13, 2026, locking in the market's 100% implied probability for the 78–79°F bin. Pre-event guidance highlighted cloud cover, scattered showers, and a moderating lake breeze that suppressed insolation and kept highs several degrees below the 83°F climatological normal, with ensemble models showing only modest spread around the mid-to-upper 70s. These conditions aligned with historical analogs featuring comparable moisture and mid-level heights that rarely produce outliers beyond a narrow range. Realistic challenges would require unexpected clearing and stronger southerly flow to push peaks into the low 80s, though post-event data eliminated that possibility.
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 13 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 13 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
$73,375End Date
Aug 13, 2026Market Opened
Aug 11, 2026, 9:02 PM ETResolution Source
https://www.wunderground.com/history/daily/us/il/chicago/KORDResolver
0x69c47De9D...Outcome proposed: No
No dispute
Final outcome: No
Official National Weather Service observations recorded a daily maximum of 78°F at Chicago-area stations on August 13, 2026, locking in the market's 100% implied probability for the 78–79°F bin. Pre-event guidance highlighted cloud cover, scattered showers, and a moderating lake breeze that suppressed insolation and kept highs several degrees below the 83°F climatological normal, with ensemble models showing only modest spread around the mid-to-upper 70s. These conditions aligned with historical analogs featuring comparable moisture and mid-level heights that rarely produce outliers beyond a narrow range. Realistic challenges would require unexpected clearing and stronger southerly flow to push peaks into the low 80s, though post-event data eliminated that possibility.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · Updated
Beware of external links.
Beware of external links.
Frequently Asked Questions