Latest National Weather Service and ensemble model guidance positions an 80-81°F high as the most probable outcome for Chicago on August 18, reflecting near-normal August conditions tempered by moderating lake breezes and possible cloud cover or scattered showers that limit peak heating. Climatological normals for the date center near 82-83°F, but recent cooler-than-average readings in the upper 70s to low 80s and variable steering patterns have kept surface heating in check. Traders assign 55% implied probability to 80-81°F and 26.5% to 82-83°F, with lower bins reflecting residual uncertainty in boundary-layer moisture and diurnal mixing ahead of the final forecast update.
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 18?
Highest temperature in Chicago on August 18?
80-81°F 55%
82-83°F 27%
78-79°F 13%
84-85°F 6%
NEW
NEW
Aug 18, 2026
71°F or below
<1%
72-73°F
<1%
74-75°F
<1%
76-77°F
3%
78-79°F
13%
80-81°F
55%
82-83°F
27%
84-85°F
6%
86-87°F
2%
88-89°F
<1%
90°F or higher
<1%
80-81°F 55%
82-83°F 27%
78-79°F 13%
84-85°F 6%
NEW
NEW
Aug 18, 2026
71°F or below
$25 Vol.
<1%
72-73°F
$233 Vol.
<1%
74-75°F
$2,788 Vol.
<1%
76-77°F
$375 Vol.
3%
78-79°F
$986 Vol.
13%
80-81°F
$1,777 Vol.
55%
82-83°F
$1,956 Vol.
27%
84-85°F
$566 Vol.
6%
86-87°F
$414 Vol.
2%
88-89°F
$295 Vol.
<1%
90°F or higher
$100 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 18 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.Latest National Weather Service and ensemble model guidance positions an 80-81°F high as the most probable outcome for Chicago on August 18, reflecting near-normal August conditions tempered by moderating lake breezes and possible cloud cover or scattered showers that limit peak heating. Climatological normals for the date center near 82-83°F, but recent cooler-than-average readings in the upper 70s to low 80s and variable steering patterns have kept surface heating in check. Traders assign 55% implied probability to 80-81°F and 26.5% to 82-83°F, with lower bins reflecting residual uncertainty in boundary-layer moisture and diurnal mixing ahead of the final forecast update.
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 18 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 18 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 16, 2026, 9:56 PM ET
Volume
$9,515End Date
Aug 18, 2026Market Opened
Aug 16, 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 18 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.Latest National Weather Service and ensemble model guidance positions an 80-81°F high as the most probable outcome for Chicago on August 18, reflecting near-normal August conditions tempered by moderating lake breezes and possible cloud cover or scattered showers that limit peak heating. Climatological normals for the date center near 82-83°F, but recent cooler-than-average readings in the upper 70s to low 80s and variable steering patterns have kept surface heating in check. Traders assign 55% implied probability to 80-81°F and 26.5% to 82-83°F, with lower bins reflecting residual uncertainty in boundary-layer moisture and diurnal mixing ahead of the final forecast update.
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 18 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 18 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
$9,515End Date
Aug 18, 2026Market Opened
Aug 16, 2026, 9:56 PM ETResolution Source
https://www.wunderground.com/history/daily/us/il/chicago/KORDResolver
0x69c47De9D...Latest National Weather Service and ensemble model guidance positions an 80-81°F high as the most probable outcome for Chicago on August 18, reflecting near-normal August conditions tempered by moderating lake breezes and possible cloud cover or scattered showers that limit peak heating. Climatological normals for the date center near 82-83°F, but recent cooler-than-average readings in the upper 70s to low 80s and variable steering patterns have kept surface heating in check. Traders assign 55% implied probability to 80-81°F and 26.5% to 82-83°F, with lower bins reflecting residual uncertainty in boundary-layer moisture and diurnal mixing ahead of the final forecast update.
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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