Official observations from the National Weather Service at San Francisco International Airport (KSFO) confirm the highest temperature on April 20 reached 64-65°F, driving Polymarket traders to a unanimous 100% implied probability on this outcome as the definitive recorded high per Weather Underground data used for resolution. Persistent marine layer and cool onshore flow under high pressure suppressed warming, aligning with pre-event National Weather Service forecasts projecting a high near 63°F amid typical mid-April climatology, where SF averages 62-65°F highs. With the observation period closed, only an exceedingly rare data revision by NOAA—such as sensor malfunction verification—could challenge this positioning, though historical precedents show such adjustments affect less than 1% of daily records. Traders await final daily climate summary for closure.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · UpdatedHighest temperature in San Francisco on April 20?
Highest temperature in San Francisco on April 20?
64-65°F 100.0%
55°F or below <1%
56-57°F <1%
58-59°F <1%
$100,951 Vol.
$100,951 Vol.
Apr 20, 2026
55°F or below
No
56-57°F
No
58-59°F
No
60-61°F
No
62-63°F
No
64-65°F
Yes
66-67°F
No
68-69°F
No
70-71°F
No
72-73°F
No
74°F or higher
No
64-65°F 100.0%
55°F or below <1%
56-57°F <1%
58-59°F <1%
$100,951 Vol.
$100,951 Vol.
Apr 20, 2026
55°F or below
$1,808 Vol.
No
56-57°F
$2,918 Vol.
No
58-59°F
$5,609 Vol.
No
60-61°F
$7,207 Vol.
No
62-63°F
$8,196 Vol.
No
64-65°F
$39,464 Vol.
Yes
66-67°F
$8,719 Vol.
No
68-69°F
$10,590 Vol.
No
70-71°F
$9,010 Vol.
No
72-73°F
$3,796 Vol.
No
74°F or higher
$3,634 Vol.
No
This market will resolve to the temperature range that contains the highest temperature recorded at the San Francisco International Airport Station in degrees Fahrenheit on 20 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 San Francisco International Airport Station once information is finalized, available here: https://www.wunderground.com/history/daily/us/ca/san-francisco/KSFO.
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 observations from the National Weather Service at San Francisco International Airport (KSFO) confirm the highest temperature on April 20 reached 64-65°F, driving Polymarket traders to a unanimous 100% implied probability on this outcome as the definitive recorded high per Weather Underground data used for resolution. Persistent marine layer and cool onshore flow under high pressure suppressed warming, aligning with pre-event National Weather Service forecasts projecting a high near 63°F amid typical mid-April climatology, where SF averages 62-65°F highs. With the observation period closed, only an exceedingly rare data revision by NOAA—such as sensor malfunction verification—could challenge this positioning, though historical precedents show such adjustments affect less than 1% of daily records. Traders await final daily climate summary for closure.
This market will resolve to the temperature range that contains the highest temperature recorded at the San Francisco International Airport Station in degrees Fahrenheit on 20 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 San Francisco International Airport Station once information is finalized, available here: https://www.wunderground.com/history/daily/us/ca/san-francisco/KSFO.
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 San Francisco International Airport Station once information is finalized, available here: https://www.wunderground.com/history/daily/us/ca/san-francisco/KSFO.
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 18, 2026, 12:40 AM ET
Volume
$100,951End Date
Apr 20, 2026Market Opened
Apr 18, 2026, 12:40 AM ETResolution Source
https://www.wunderground.com/history/daily/us/ca/san-francisco/KSFOResolver
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 San Francisco International Airport Station in degrees Fahrenheit on 20 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 San Francisco International Airport Station once information is finalized, available here: https://www.wunderground.com/history/daily/us/ca/san-francisco/KSFO.
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 observations from the National Weather Service at San Francisco International Airport (KSFO) confirm the highest temperature on April 20 reached 64-65°F, driving Polymarket traders to a unanimous 100% implied probability on this outcome as the definitive recorded high per Weather Underground data used for resolution. Persistent marine layer and cool onshore flow under high pressure suppressed warming, aligning with pre-event National Weather Service forecasts projecting a high near 63°F amid typical mid-April climatology, where SF averages 62-65°F highs. With the observation period closed, only an exceedingly rare data revision by NOAA—such as sensor malfunction verification—could challenge this positioning, though historical precedents show such adjustments affect less than 1% of daily records. Traders await final daily climate summary for closure.
This market will resolve to the temperature range that contains the highest temperature recorded at the San Francisco International Airport Station in degrees Fahrenheit on 20 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 San Francisco International Airport Station once information is finalized, available here: https://www.wunderground.com/history/daily/us/ca/san-francisco/KSFO.
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 San Francisco International Airport Station once information is finalized, available here: https://www.wunderground.com/history/daily/us/ca/san-francisco/KSFO.
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
$100,951End Date
Apr 20, 2026Market Opened
Apr 18, 2026, 12:40 AM ETResolution Source
https://www.wunderground.com/history/daily/us/ca/san-francisco/KSFOResolver
0x69c47De9D...Outcome proposed: No
No dispute
Final outcome: No
Official observations from the National Weather Service at San Francisco International Airport (KSFO) confirm the highest temperature on April 20 reached 64-65°F, driving Polymarket traders to a unanimous 100% implied probability on this outcome as the definitive recorded high per Weather Underground data used for resolution. Persistent marine layer and cool onshore flow under high pressure suppressed warming, aligning with pre-event National Weather Service forecasts projecting a high near 63°F amid typical mid-April climatology, where SF averages 62-65°F highs. With the observation period closed, only an exceedingly rare data revision by NOAA—such as sensor malfunction verification—could challenge this positioning, though historical precedents show such adjustments affect less than 1% of daily records. Traders await final daily climate summary for closure.
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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