Official National Weather Service guidance and multiple forecast models point to a high near 70°F for Chicago on September 18 under partly sunny skies with easterly winds of 10–15 mph moderating lake-influenced air. Persistent cloud cover from overnight moisture and a stable atmospheric profile limit afternoon warming, keeping readings in the low to mid-70s at most. Market pricing reflects this consensus while assigning slightly higher odds to 72–73°F, likely due to minor model spreads on cloud timing and any late-day clearing. Historical September averages near 75°F provide context, yet recent cool anomalies and the approaching frontal boundary support the lower range. No significant forecast revisions are anticipated before resolution.
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 18?
Highest temperature in Chicago on September 18?
72-73°F 36%
70-71°F 33%
74-75°F 20%
68-69°F 13%
NEW
$16,712 Vol.
NEW
$16,712 Vol.
Sep 18, 2026
63°F or below
<1%
64-65°F
<1%
66-67°F
<1%
68-69°F
13%
70-71°F
33%
72-73°F
36%
74-75°F
20%
76-77°F
2%
78-79°F
1%
80-81°F
<1%
82°F or higher
<1%
72-73°F 36%
70-71°F 33%
74-75°F 20%
68-69°F 13%
NEW
$16,712 Vol.
NEW
$16,712 Vol.
Sep 18, 2026
63°F or below
$263 Vol.
<1%
64-65°F
$270 Vol.
<1%
66-67°F
$128 Vol.
<1%
68-69°F
$4,948 Vol.
13%
70-71°F
$3,773 Vol.
33%
72-73°F
$2,830 Vol.
36%
74-75°F
$2,527 Vol.
20%
76-77°F
$936 Vol.
2%
78-79°F
$306 Vol.
1%
80-81°F
$486 Vol.
<1%
82°F or higher
$243 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 18 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.Official National Weather Service guidance and multiple forecast models point to a high near 70°F for Chicago on September 18 under partly sunny skies with easterly winds of 10–15 mph moderating lake-influenced air. Persistent cloud cover from overnight moisture and a stable atmospheric profile limit afternoon warming, keeping readings in the low to mid-70s at most. Market pricing reflects this consensus while assigning slightly higher odds to 72–73°F, likely due to minor model spreads on cloud timing and any late-day clearing. Historical September averages near 75°F provide context, yet recent cool anomalies and the approaching frontal boundary support the lower range. No significant forecast revisions are anticipated before resolution.
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 18 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 16, 2026, 3:56 AM ET
Volume
$16,712End Date
Sep 18, 2026Market Opened
Sep 16, 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 18 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.Official National Weather Service guidance and multiple forecast models point to a high near 70°F for Chicago on September 18 under partly sunny skies with easterly winds of 10–15 mph moderating lake-influenced air. Persistent cloud cover from overnight moisture and a stable atmospheric profile limit afternoon warming, keeping readings in the low to mid-70s at most. Market pricing reflects this consensus while assigning slightly higher odds to 72–73°F, likely due to minor model spreads on cloud timing and any late-day clearing. Historical September averages near 75°F provide context, yet recent cool anomalies and the approaching frontal boundary support the lower range. No significant forecast revisions are anticipated before resolution.
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 18 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
$16,712End Date
Sep 18, 2026Market Opened
Sep 16, 2026, 3:56 AM ETResolution Source
https://www.weather.gov/wrh/timeseries?site=kordResolver
0x69c47De9D...Official National Weather Service guidance and multiple forecast models point to a high near 70°F for Chicago on September 18 under partly sunny skies with easterly winds of 10–15 mph moderating lake-influenced air. Persistent cloud cover from overnight moisture and a stable atmospheric profile limit afternoon warming, keeping readings in the low to mid-70s at most. Market pricing reflects this consensus while assigning slightly higher odds to 72–73°F, likely due to minor model spreads on cloud timing and any late-day clearing. Historical September averages near 75°F provide context, yet recent cool anomalies and the approaching frontal boundary support the lower range. No significant forecast revisions are anticipated before resolution.
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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