Recent National Weather Service and AccuWeather guidance points to an overnight low near 62–65°F in Chicago on August 21, aligning with the historical average of 64.7°F and driving the tight clustering of market-implied odds around 54–65°F. Primary factors include radiative cooling under partly cloudy skies, light winds limiting turbulent mixing, and Lake Michigan’s moderating influence via lake breezes that reduce the urban-rural temperature gradient. Model consensus shows modest spread due to variable cloud timing and dewpoint depressions, while urban heat island effects and exact station resolution (O’Hare versus Midway) introduce additional uncertainty. Traders are monitoring updated forecast runs and real-time observations for any shifts in these boundary-layer conditions.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · UpdatedLowest temperature in Chicago on August 21?
Lowest temperature in Chicago on August 21?
58-59°F 36%
60-61°F 36%
62-63°F 35%
54-55°F 34%
NEW
NEW
Aug 21, 2026
51°F or below
<1%
52-53°F
8%
54-55°F
34%
56-57°F
34%
58-59°F
36%
60-61°F
36%
62-63°F
35%
64-65°F
34%
66-67°F
<1%
68-69°F
1%
70°F or higher
<1%
58-59°F 36%
60-61°F 36%
62-63°F 35%
54-55°F 34%
NEW
NEW
Aug 21, 2026
51°F or below
$120 Vol.
<1%
52-53°F
$115 Vol.
8%
54-55°F
$0 Vol.
34%
56-57°F
$0 Vol.
34%
58-59°F
$0 Vol.
36%
60-61°F
$1 Vol.
36%
62-63°F
$1 Vol.
35%
64-65°F
$0 Vol.
34%
66-67°F
$217 Vol.
<1%
68-69°F
$131 Vol.
1%
70°F or higher
$179 Vol.
<1%
This market will resolve based on the lowest 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 lowest 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 lowest 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.Recent National Weather Service and AccuWeather guidance points to an overnight low near 62–65°F in Chicago on August 21, aligning with the historical average of 64.7°F and driving the tight clustering of market-implied odds around 54–65°F. Primary factors include radiative cooling under partly cloudy skies, light winds limiting turbulent mixing, and Lake Michigan’s moderating influence via lake breezes that reduce the urban-rural temperature gradient. Model consensus shows modest spread due to variable cloud timing and dewpoint depressions, while urban heat island effects and exact station resolution (O’Hare versus Midway) introduce additional uncertainty. Traders are monitoring updated forecast runs and real-time observations for any shifts in these boundary-layer conditions.
This market will resolve based on the lowest 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 lowest 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 lowest 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 lowest 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 lowest 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 20, 2026, 1:28 PM ET
Volume
$764End Date
Aug 21, 2026Market Opened
Aug 20, 2026, 1:28 PM ETResolution Source
https://www.wunderground.com/history/daily/us/il/chicago/KORDResolver
0x69c47De9D...This market will resolve based on the lowest 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 lowest 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 lowest 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.Recent National Weather Service and AccuWeather guidance points to an overnight low near 62–65°F in Chicago on August 21, aligning with the historical average of 64.7°F and driving the tight clustering of market-implied odds around 54–65°F. Primary factors include radiative cooling under partly cloudy skies, light winds limiting turbulent mixing, and Lake Michigan’s moderating influence via lake breezes that reduce the urban-rural temperature gradient. Model consensus shows modest spread due to variable cloud timing and dewpoint depressions, while urban heat island effects and exact station resolution (O’Hare versus Midway) introduce additional uncertainty. Traders are monitoring updated forecast runs and real-time observations for any shifts in these boundary-layer conditions.
This market will resolve based on the lowest 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 lowest 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 lowest 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 lowest 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 lowest 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
$764End Date
Aug 21, 2026Market Opened
Aug 20, 2026, 1:28 PM ETResolution Source
https://www.wunderground.com/history/daily/us/il/chicago/KORDResolver
0x69c47De9D...Recent National Weather Service and AccuWeather guidance points to an overnight low near 62–65°F in Chicago on August 21, aligning with the historical average of 64.7°F and driving the tight clustering of market-implied odds around 54–65°F. Primary factors include radiative cooling under partly cloudy skies, light winds limiting turbulent mixing, and Lake Michigan’s moderating influence via lake breezes that reduce the urban-rural temperature gradient. Model consensus shows modest spread due to variable cloud timing and dewpoint depressions, while urban heat island effects and exact station resolution (O’Hare versus Midway) introduce additional uncertainty. Traders are monitoring updated forecast runs and real-time observations for any shifts in these boundary-layer conditions.
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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