National Weather Service observations at San Francisco International Airport and downtown stations recorded a daily maximum of 68–69 °F on May 21, locking in the market-implied outcome. Persistent marine-layer stratus and a moderate onshore flow suppressed solar heating despite mostly sunny skies, keeping temperatures near the seasonal average of 65–67 °F. Light west-southwest winds and the typical afternoon sea breeze further capped any inland warming, consistent with long-term climatology for late-May coastal conditions. Only a significant delay in the marine layer or an anomalous offshore flow could have pushed readings into the low 70s, scenarios not supported by the day’s official data or model guidance.
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 May 21?
Highest temperature in San Francisco on May 21?
68-69°F 100.0%
57°F or below <1%
58-59°F <1%
60-61°F <1%
$53,238 Vol.
$53,238 Vol.
May 21, 2026
57°F or below
No
58-59°F
No
60-61°F
No
62-63°F
No
64-65°F
No
66-67°F
No
68-69°F
Yes
70-71°F
No
72-73°F
No
74-75°F
No
76°F or higher
No
68-69°F 100.0%
57°F or below <1%
58-59°F <1%
60-61°F <1%
$53,238 Vol.
$53,238 Vol.
May 21, 2026
57°F or below
$3,485 Vol.
No
58-59°F
$3,109 Vol.
No
60-61°F
$1,099 Vol.
No
62-63°F
$3,831 Vol.
No
64-65°F
$1,275 Vol.
No
66-67°F
$5,094 Vol.
No
68-69°F
$11,813 Vol.
Yes
70-71°F
$8,602 Vol.
No
72-73°F
$5,011 Vol.
No
74-75°F
$4,051 Vol.
No
76°F or higher
$5,868 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 21 May '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.National Weather Service observations at San Francisco International Airport and downtown stations recorded a daily maximum of 68–69 °F on May 21, locking in the market-implied outcome. Persistent marine-layer stratus and a moderate onshore flow suppressed solar heating despite mostly sunny skies, keeping temperatures near the seasonal average of 65–67 °F. Light west-southwest winds and the typical afternoon sea breeze further capped any inland warming, consistent with long-term climatology for late-May coastal conditions. Only a significant delay in the marine layer or an anomalous offshore flow could have pushed readings into the low 70s, scenarios not supported by the day’s official data or model guidance.
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 21 May '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: May 19, 2026, 12:07 AM ET
Volume
$53,238End Date
May 21, 2026Market Opened
May 19, 2026, 12:07 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 21 May '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.National Weather Service observations at San Francisco International Airport and downtown stations recorded a daily maximum of 68–69 °F on May 21, locking in the market-implied outcome. Persistent marine-layer stratus and a moderate onshore flow suppressed solar heating despite mostly sunny skies, keeping temperatures near the seasonal average of 65–67 °F. Light west-southwest winds and the typical afternoon sea breeze further capped any inland warming, consistent with long-term climatology for late-May coastal conditions. Only a significant delay in the marine layer or an anomalous offshore flow could have pushed readings into the low 70s, scenarios not supported by the day’s official data or model guidance.
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 21 May '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
$53,238End Date
May 21, 2026Market Opened
May 19, 2026, 12:07 AM ETResolution Source
https://www.wunderground.com/history/daily/us/ca/san-francisco/KSFOResolver
0x69c47De9D...Outcome proposed: No
No dispute
Final outcome: No
National Weather Service observations at San Francisco International Airport and downtown stations recorded a daily maximum of 68–69 °F on May 21, locking in the market-implied outcome. Persistent marine-layer stratus and a moderate onshore flow suppressed solar heating despite mostly sunny skies, keeping temperatures near the seasonal average of 65–67 °F. Light west-southwest winds and the typical afternoon sea breeze further capped any inland warming, consistent with long-term climatology for late-May coastal conditions. Only a significant delay in the marine layer or an anomalous offshore flow could have pushed readings into the low 70s, scenarios not supported by the day’s official data or model guidance.
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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