**Official National Weather Service observations from Chicago O’Hare on September 12, 2026, recorded a daily maximum of 88 °F under mostly sunny skies with light to moderate west-southwest winds, placing the high squarely in the market’s dominant 86-87 °F outcome.** Pre-event model consensus and climatological normals (historical September 12 average high near 77 °F) had pointed to mid-to-upper 80s, and the observed value aligned with that guidance rather than any late intensification from anomalous warmth or calm conditions. With resolution now based on verified station data, the near-100 % market-implied probability reflects the absence of measurement uncertainty or alternative reporting sources that could shift the result into the 88-89 °F bin. The only realistic challenges would involve a revised official climatological summary or a switch to a secondary station (such as Midway) showing a meaningfully different peak, both of which remain low-probability events given standard NWS procedures.
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 12?
Highest temperature in Chicago on September 12?
86-87°F 100.0%
73°F or below <1%
74-75°F <1%
76-77°F <1%
$50,178 Vol.
$50,178 Vol.
Sep 12, 2026
73°F or below
No
74-75°F
No
76-77°F
No
78-79°F
No
80-81°F
No
82-83°F
No
84-85°F
No
86-87°F
Yes
88-89°F
No
90-91°F
No
92°F or higher
No
86-87°F 100.0%
73°F or below <1%
74-75°F <1%
76-77°F <1%
$50,178 Vol.
$50,178 Vol.
Sep 12, 2026
73°F or below
$508 Vol.
No
74-75°F
$508 Vol.
No
76-77°F
$200 Vol.
No
78-79°F
$327 Vol.
No
80-81°F
$1,488 Vol.
No
82-83°F
$4,219 Vol.
No
84-85°F
$8,882 Vol.
No
86-87°F
$17,987 Vol.
Yes
88-89°F
$6,257 Vol.
No
90-91°F
$5,873 Vol.
No
92°F or higher
$3,927 Vol.
No
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 12 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 observations from Chicago O’Hare on September 12, 2026, recorded a daily maximum of 88 °F under mostly sunny skies with light to moderate west-southwest winds, placing the high squarely in the market’s dominant 86-87 °F outcome.** Pre-event model consensus and climatological normals (historical September 12 average high near 77 °F) had pointed to mid-to-upper 80s, and the observed value aligned with that guidance rather than any late intensification from anomalous warmth or calm conditions. With resolution now based on verified station data, the near-100 % market-implied probability reflects the absence of measurement uncertainty or alternative reporting sources that could shift the result into the 88-89 °F bin. The only realistic challenges would involve a revised official climatological summary or a switch to a secondary station (such as Midway) showing a meaningfully different peak, both of which remain low-probability events given standard NWS procedures.
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 12 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 10, 2026, 2:56 AM ET
Volume
$50,178End Date
Sep 12, 2026Market Opened
Sep 10, 2026, 2:56 AM ETResolution Source
https://www.weather.gov/wrh/timeseries?site=kordResolver
0x69c47De9D...Outcome proposed: No
No dispute
Final outcome: No
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 12 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 observations from Chicago O’Hare on September 12, 2026, recorded a daily maximum of 88 °F under mostly sunny skies with light to moderate west-southwest winds, placing the high squarely in the market’s dominant 86-87 °F outcome.** Pre-event model consensus and climatological normals (historical September 12 average high near 77 °F) had pointed to mid-to-upper 80s, and the observed value aligned with that guidance rather than any late intensification from anomalous warmth or calm conditions. With resolution now based on verified station data, the near-100 % market-implied probability reflects the absence of measurement uncertainty or alternative reporting sources that could shift the result into the 88-89 °F bin. The only realistic challenges would involve a revised official climatological summary or a switch to a secondary station (such as Midway) showing a meaningfully different peak, both of which remain low-probability events given standard NWS procedures.
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 12 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
$50,178End Date
Sep 12, 2026Market Opened
Sep 10, 2026, 2:56 AM ETResolution Source
https://www.weather.gov/wrh/timeseries?site=kordResolver
0x69c47De9D...Outcome proposed: No
No dispute
Final outcome: No
**Official National Weather Service observations from Chicago O’Hare on September 12, 2026, recorded a daily maximum of 88 °F under mostly sunny skies with light to moderate west-southwest winds, placing the high squarely in the market’s dominant 86-87 °F outcome.** Pre-event model consensus and climatological normals (historical September 12 average high near 77 °F) had pointed to mid-to-upper 80s, and the observed value aligned with that guidance rather than any late intensification from anomalous warmth or calm conditions. With resolution now based on verified station data, the near-100 % market-implied probability reflects the absence of measurement uncertainty or alternative reporting sources that could shift the result into the 88-89 °F bin. The only realistic challenges would involve a revised official climatological summary or a switch to a secondary station (such as Midway) showing a meaningfully different peak, both of which remain low-probability events given standard NWS procedures.
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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