Persistent northeasterly flow and mostly cloudy skies are suppressing Chicago's high temperature on September 23, with National Weather Service point forecasts and ensemble guidance converging on a maximum near 64–66°F. This represents a notable departure from the 1991–2020 climatological average of roughly 73°F, driven by post-frontal conditions and onshore winds off Lake Michigan that limit daytime heating. Recent model runs show little day-to-day shift, keeping the 64–67°F bin as the clear market favorite at 84% combined implied probability. Traders are pricing in high confidence in this narrow range while assigning minimal weight to warmer or cooler outliers, consistent with stable short-range guidance ahead of tomorrow’s observation window.
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 September 23?
Highest temperature in Chicago on September 23?
66-67°F 48%
64-65°F 36%
68-69°F 11%
62-63°F 8%
NEW
$18,681 Vol.
NEW
$18,681 Vol.
Sep 23, 2026
55°F or below
<1%
56-57°F
<1%
58-59°F
<1%
60-61°F
2%
62-63°F
8%
64-65°F
36%
66-67°F
48%
68-69°F
11%
70-71°F
<1%
72-73°F
<1%
74°F or higher
<1%
66-67°F 48%
64-65°F 36%
68-69°F 11%
62-63°F 8%
NEW
$18,681 Vol.
NEW
$18,681 Vol.
Sep 23, 2026
55°F or below
$215 Vol.
<1%
56-57°F
$95 Vol.
<1%
58-59°F
$95 Vol.
<1%
60-61°F
$2,548 Vol.
2%
62-63°F
$2,322 Vol.
8%
64-65°F
$4,327 Vol.
36%
66-67°F
$4,922 Vol.
48%
68-69°F
$2,800 Vol.
11%
70-71°F
$1,168 Vol.
<1%
72-73°F
$95 Vol.
<1%
74°F or higher
$95 Vol.
<1%
This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the Chicago O'Hare Intl Airport Station in degrees Fahrenheit on 23 Sep '26.
The resolution source for this market will be information from NOAA, specifically the highest reading under the "Temp" column for all times on this day, available here: https://www.weather.gov/wrh/timeseries?site=kord
This market will resolve off of the Hourly Data provided using the "Show Hourly Data" button.
If NOAA data for the observation date is unavailable by 11:59 PM ET on the day following the observation date, the Weather Underground Daily Observations table will be used as the resolution source.
In the event that there is no data for the observation date by 11:59 PM ET on the day following the observation date, this market will resolve to the lowest bracket.
To toggle between Fahrenheit and Celsius, click the "Switch to US Units w/ kts" button until the relevant table displays °F.
This market will resolve once the first data point for the following date has been published on the resolution source, or by 11:59 PM ET on the day following the observation date, whichever comes first.
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.Persistent northeasterly flow and mostly cloudy skies are suppressing Chicago's high temperature on September 23, with National Weather Service point forecasts and ensemble guidance converging on a maximum near 64–66°F. This represents a notable departure from the 1991–2020 climatological average of roughly 73°F, driven by post-frontal conditions and onshore winds off Lake Michigan that limit daytime heating. Recent model runs show little day-to-day shift, keeping the 64–67°F bin as the clear market favorite at 84% combined implied probability. Traders are pricing in high confidence in this narrow range while assigning minimal weight to warmer or cooler outliers, consistent with stable short-range guidance ahead of tomorrow’s observation window.
This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the Chicago O'Hare Intl Airport Station in degrees Fahrenheit on 23 Sep '26.
The resolution source for this market will be information from NOAA, specifically the highest reading under the "Temp" column for all times on this day, available here: https://www.weather.gov/wrh/timeseries?site=kord
This market will resolve off of the Hourly Data provided using the "Show Hourly Data" button.
If NOAA data for the observation date is unavailable by 11:59 PM ET on the day following the observation date, the Weather Underground Daily Observations table will be used as the resolution source.
In the event that there is no data for the observation date by 11:59 PM ET on the day following the observation date, this market will resolve to the lowest bracket.
To toggle between Fahrenheit and Celsius, click the "Switch to US Units w/ kts" button until the relevant table displays °F.
This market will resolve once the first data point for the following date has been published on the resolution source, or by 11:59 PM ET on the day following the observation date, whichever comes first.
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.
The resolution source for this market will be information from NOAA, specifically the highest reading under the "Temp" column for all times on this day, available here: https://www.weather.gov/wrh/timeseries?site=kord
This market will resolve off of the Hourly Data provided using the "Show Hourly Data" button.
If NOAA data for the observation date is unavailable by 11:59 PM ET on the day following the observation date, the Weather Underground Daily Observations table will be used as the resolution source.
In the event that there is no data for the observation date by 11:59 PM ET on the day following the observation date, this market will resolve to the lowest bracket.
To toggle between Fahrenheit and Celsius, click the "Switch to US Units w/ kts" button until the relevant table displays °F.
This market will resolve once the first data point for the following date has been published on the resolution source, or by 11:59 PM ET on the day following the observation date, whichever comes first.
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: Sep 21, 2026, 3:56 AM ET
Volume
$18,681End Date
Sep 23, 2026Market Opened
Sep 21, 2026, 3:56 AM ETResolution Source
https://www.weather.gov/wrh/timeseries?site=kordResolver
0x69c47De9D...This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the Chicago O'Hare Intl Airport Station in degrees Fahrenheit on 23 Sep '26.
The resolution source for this market will be information from NOAA, specifically the highest reading under the "Temp" column for all times on this day, available here: https://www.weather.gov/wrh/timeseries?site=kord
This market will resolve off of the Hourly Data provided using the "Show Hourly Data" button.
If NOAA data for the observation date is unavailable by 11:59 PM ET on the day following the observation date, the Weather Underground Daily Observations table will be used as the resolution source.
In the event that there is no data for the observation date by 11:59 PM ET on the day following the observation date, this market will resolve to the lowest bracket.
To toggle between Fahrenheit and Celsius, click the "Switch to US Units w/ kts" button until the relevant table displays °F.
This market will resolve once the first data point for the following date has been published on the resolution source, or by 11:59 PM ET on the day following the observation date, whichever comes first.
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.Persistent northeasterly flow and mostly cloudy skies are suppressing Chicago's high temperature on September 23, with National Weather Service point forecasts and ensemble guidance converging on a maximum near 64–66°F. This represents a notable departure from the 1991–2020 climatological average of roughly 73°F, driven by post-frontal conditions and onshore winds off Lake Michigan that limit daytime heating. Recent model runs show little day-to-day shift, keeping the 64–67°F bin as the clear market favorite at 84% combined implied probability. Traders are pricing in high confidence in this narrow range while assigning minimal weight to warmer or cooler outliers, consistent with stable short-range guidance ahead of tomorrow’s observation window.
This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the Chicago O'Hare Intl Airport Station in degrees Fahrenheit on 23 Sep '26.
The resolution source for this market will be information from NOAA, specifically the highest reading under the "Temp" column for all times on this day, available here: https://www.weather.gov/wrh/timeseries?site=kord
This market will resolve off of the Hourly Data provided using the "Show Hourly Data" button.
If NOAA data for the observation date is unavailable by 11:59 PM ET on the day following the observation date, the Weather Underground Daily Observations table will be used as the resolution source.
In the event that there is no data for the observation date by 11:59 PM ET on the day following the observation date, this market will resolve to the lowest bracket.
To toggle between Fahrenheit and Celsius, click the "Switch to US Units w/ kts" button until the relevant table displays °F.
This market will resolve once the first data point for the following date has been published on the resolution source, or by 11:59 PM ET on the day following the observation date, whichever comes first.
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.
The resolution source for this market will be information from NOAA, specifically the highest reading under the "Temp" column for all times on this day, available here: https://www.weather.gov/wrh/timeseries?site=kord
This market will resolve off of the Hourly Data provided using the "Show Hourly Data" button.
If NOAA data for the observation date is unavailable by 11:59 PM ET on the day following the observation date, the Weather Underground Daily Observations table will be used as the resolution source.
In the event that there is no data for the observation date by 11:59 PM ET on the day following the observation date, this market will resolve to the lowest bracket.
To toggle between Fahrenheit and Celsius, click the "Switch to US Units w/ kts" button until the relevant table displays °F.
This market will resolve once the first data point for the following date has been published on the resolution source, or by 11:59 PM ET on the day following the observation date, whichever comes first.
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
$18,681End Date
Sep 23, 2026Market Opened
Sep 21, 2026, 3:56 AM ETResolution Source
https://www.weather.gov/wrh/timeseries?site=kordResolver
0x69c47De9D...Persistent northeasterly flow and mostly cloudy skies are suppressing Chicago's high temperature on September 23, with National Weather Service point forecasts and ensemble guidance converging on a maximum near 64–66°F. This represents a notable departure from the 1991–2020 climatological average of roughly 73°F, driven by post-frontal conditions and onshore winds off Lake Michigan that limit daytime heating. Recent model runs show little day-to-day shift, keeping the 64–67°F bin as the clear market favorite at 84% combined implied probability. Traders are pricing in high confidence in this narrow range while assigning minimal weight to warmer or cooler outliers, consistent with stable short-range guidance ahead of tomorrow’s observation window.
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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