Official National Weather Service observations from Chicago O'Hare International Airport (KORD), the market's authoritative station, confirm a maximum temperature of 63°F on April 18, 2026, at 12:12 AM local standard time, aligning precisely with the 62-63°F outcome commanding 100% market-implied probability. Persistent rain, light rain, and fog—coupled with an advancing upper-level trough ushering cooler mid-level air—suppressed highs well below the prior day's near-73°F peak and the 60°F climatological normal, as detailed in the NWS Chicago daily climatological report. This trader consensus, backed by real capital, reflects verified measurements from automated surface observing systems. Realistic challenges are minimal but could include rare post-preliminary data revisions or instrumentation anomalies, though historical precedents show such adjustments seldom exceed 1-2°F.
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 April 18?
Highest temperature in Chicago on April 18?
62-63°F 100.0%
53°F or below <1%
54-55°F <1%
56-57°F <1%
$253,090 Vol.
$253,090 Vol.
Apr 18, 2026
53°F or below
No
54-55°F
No
56-57°F
No
58-59°F
No
60-61°F
No
62-63°F
Yes
64-65°F
No
66-67°F
No
68-69°F
No
70-71°F
No
72°F or higher
No
62-63°F 100.0%
53°F or below <1%
54-55°F <1%
56-57°F <1%
$253,090 Vol.
$253,090 Vol.
Apr 18, 2026
53°F or below
$60,923 Vol.
No
54-55°F
$11,656 Vol.
No
56-57°F
$10,943 Vol.
No
58-59°F
$13,612 Vol.
No
60-61°F
$14,188 Vol.
No
62-63°F
$40,394 Vol.
Yes
64-65°F
$26,372 Vol.
No
66-67°F
$17,156 Vol.
No
68-69°F
$15,814 Vol.
No
70-71°F
$21,157 Vol.
No
72°F or higher
$20,874 Vol.
No
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 Apr '26.
The resolution source for this market will be information from Wunderground, specifically the highest temperature recorded for all times on this day by the Forecast for the Chicago O'Hare Intl Airport Station once information is finalized, 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 to "Yes" until all data for this date has been finalized.
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.
Any revisions to temperatures recorded after data is finalized for this market's timeframe will not be considered for this market's resolution.Official National Weather Service observations from Chicago O'Hare International Airport (KORD), the market's authoritative station, confirm a maximum temperature of 63°F on April 18, 2026, at 12:12 AM local standard time, aligning precisely with the 62-63°F outcome commanding 100% market-implied probability. Persistent rain, light rain, and fog—coupled with an advancing upper-level trough ushering cooler mid-level air—suppressed highs well below the prior day's near-73°F peak and the 60°F climatological normal, as detailed in the NWS Chicago daily climatological report. This trader consensus, backed by real capital, reflects verified measurements from automated surface observing systems. Realistic challenges are minimal but could include rare post-preliminary data revisions or instrumentation anomalies, though historical precedents show such adjustments seldom exceed 1-2°F.
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 Apr '26.
The resolution source for this market will be information from Wunderground, specifically the highest temperature recorded for all times on this day by the Forecast for the Chicago O'Hare Intl Airport Station once information is finalized, 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 to "Yes" until all data for this date has been finalized.
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.
Any revisions to temperatures recorded after data is finalized for this market's timeframe will not be considered for this market's resolution.
The resolution source for this market will be information from Wunderground, specifically the highest temperature recorded for all times on this day by the Forecast for the Chicago O'Hare Intl Airport Station once information is finalized, 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 to "Yes" until all data for this date has been finalized.
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.
Any revisions to temperatures recorded after data is finalized for this market's timeframe will not be considered for this market's resolution.
Market Opened: Apr 16, 2026, 12:41 AM ET
Volume
$253,090End Date
Apr 18, 2026Market Opened
Apr 16, 2026, 12:41 AM ETResolution Source
https://www.wunderground.com/history/daily/us/il/chicago/KORDResolver
0x69c47De9D...Outcome proposed: No
No dispute
Final outcome: No
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 Apr '26.
The resolution source for this market will be information from Wunderground, specifically the highest temperature recorded for all times on this day by the Forecast for the Chicago O'Hare Intl Airport Station once information is finalized, 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 to "Yes" until all data for this date has been finalized.
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.
Any revisions to temperatures recorded after data is finalized for this market's timeframe will not be considered for this market's resolution.Official National Weather Service observations from Chicago O'Hare International Airport (KORD), the market's authoritative station, confirm a maximum temperature of 63°F on April 18, 2026, at 12:12 AM local standard time, aligning precisely with the 62-63°F outcome commanding 100% market-implied probability. Persistent rain, light rain, and fog—coupled with an advancing upper-level trough ushering cooler mid-level air—suppressed highs well below the prior day's near-73°F peak and the 60°F climatological normal, as detailed in the NWS Chicago daily climatological report. This trader consensus, backed by real capital, reflects verified measurements from automated surface observing systems. Realistic challenges are minimal but could include rare post-preliminary data revisions or instrumentation anomalies, though historical precedents show such adjustments seldom exceed 1-2°F.
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 Apr '26.
The resolution source for this market will be information from Wunderground, specifically the highest temperature recorded for all times on this day by the Forecast for the Chicago O'Hare Intl Airport Station once information is finalized, 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 to "Yes" until all data for this date has been finalized.
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.
Any revisions to temperatures recorded after data is finalized for this market's timeframe will not be considered for this market's resolution.
The resolution source for this market will be information from Wunderground, specifically the highest temperature recorded for all times on this day by the Forecast for the Chicago O'Hare Intl Airport Station once information is finalized, 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 to "Yes" until all data for this date has been finalized.
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.
Any revisions to temperatures recorded after data is finalized for this market's timeframe will not be considered for this market's resolution.
Volume
$253,090End Date
Apr 18, 2026Market Opened
Apr 16, 2026, 12:41 AM ETResolution Source
https://www.wunderground.com/history/daily/us/il/chicago/KORDResolver
0x69c47De9D...Outcome proposed: No
No dispute
Final outcome: No
Official National Weather Service observations from Chicago O'Hare International Airport (KORD), the market's authoritative station, confirm a maximum temperature of 63°F on April 18, 2026, at 12:12 AM local standard time, aligning precisely with the 62-63°F outcome commanding 100% market-implied probability. Persistent rain, light rain, and fog—coupled with an advancing upper-level trough ushering cooler mid-level air—suppressed highs well below the prior day's near-73°F peak and the 60°F climatological normal, as detailed in the NWS Chicago daily climatological report. This trader consensus, backed by real capital, reflects verified measurements from automated surface observing systems. Realistic challenges are minimal but could include rare post-preliminary data revisions or instrumentation anomalies, though historical precedents show such adjustments seldom exceed 1-2°F.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · Updated
Beware of external links.
Beware of external links.
Frequently Asked Questions