Persistent marine layer conditions driven by a stationary low-pressure system in the eastern Pacific and high pressure over the Four Corners have kept San Francisco highs tightly clustered in the mid- to upper-60s°F through mid-August, aligning trader focus on the 68-69°F bin. Onshore flow from the cold California Current and a deep marine layer capped at several thousand feet suppress daytime warming and promote fog or low stratus that limit solar heating, consistent with NOAA climatology showing typical August maxima near 67°F. Recent observations confirm a multi-day streak of 66-68°F readings with minimal model spread for August 21, though subtle subsidence or marine layer thinning could briefly allow 70-71°F. These dynamics explain the heavy weighting toward 66-69°F outcomes while underscoring forecast sensitivity to small changes in boundary-layer moisture or wind patterns.
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 August 21?
Highest temperature in San Francisco on August 21?
68-69°F 45%
66-67°F 25%
70-71°F 21%
64-65°F 6%
NEW
NEW
Aug 21, 2026
61°F or below
1%
62-63°F
2%
64-65°F
6%
66-67°F
25%
68-69°F
45%
70-71°F
21%
72-73°F
6%
74-75°F
1%
76-77°F
<1%
78-79°F
<1%
80°F or higher
<1%
68-69°F 45%
66-67°F 25%
70-71°F 21%
64-65°F 6%
NEW
NEW
Aug 21, 2026
61°F or below
$145 Vol.
1%
62-63°F
$285 Vol.
2%
64-65°F
$1,050 Vol.
6%
66-67°F
$899 Vol.
25%
68-69°F
$1,328 Vol.
45%
70-71°F
$1,240 Vol.
21%
72-73°F
$993 Vol.
6%
74-75°F
$1,106 Vol.
1%
76-77°F
$279 Vol.
<1%
78-79°F
$182 Vol.
<1%
80°F or higher
$79 Vol.
<1%
This market will resolve based on the highest temperature recorded in the 'Daily Observations' table on Weather Underground, not the figure displayed in the 'Day High & Low' summary section; in the event of any discrepancy between the two, the Daily Observations table shall be the primary resolution source not the Day High & Low section.
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 Aug '26.
The resolution source for this market will be information from Wunderground, specifically the highest temperature recorded for all times on this day for the San Francisco International Airport Station, 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 until the first data point for the following date has been published on the resolution source.
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.Persistent marine layer conditions driven by a stationary low-pressure system in the eastern Pacific and high pressure over the Four Corners have kept San Francisco highs tightly clustered in the mid- to upper-60s°F through mid-August, aligning trader focus on the 68-69°F bin. Onshore flow from the cold California Current and a deep marine layer capped at several thousand feet suppress daytime warming and promote fog or low stratus that limit solar heating, consistent with NOAA climatology showing typical August maxima near 67°F. Recent observations confirm a multi-day streak of 66-68°F readings with minimal model spread for August 21, though subtle subsidence or marine layer thinning could briefly allow 70-71°F. These dynamics explain the heavy weighting toward 66-69°F outcomes while underscoring forecast sensitivity to small changes in boundary-layer moisture or wind patterns.
This market will resolve based on the highest temperature recorded in the 'Daily Observations' table on Weather Underground, not the figure displayed in the 'Day High & Low' summary section; in the event of any discrepancy between the two, the Daily Observations table shall be the primary resolution source not the Day High & Low section.
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 Aug '26.
The resolution source for this market will be information from Wunderground, specifically the highest temperature recorded for all times on this day for the San Francisco International Airport Station, 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 until the first data point for the following date has been published on the resolution source.
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.
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 Aug '26.
The resolution source for this market will be information from Wunderground, specifically the highest temperature recorded for all times on this day for the San Francisco International Airport Station, 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 until the first data point for the following date has been published on the resolution source.
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: Aug 19, 2026, 9:57 PM ET
Volume
$7,586End Date
Aug 21, 2026Market Opened
Aug 19, 2026, 9:57 PM ETResolution Source
https://www.wunderground.com/history/daily/us/ca/san-francisco/KSFOResolver
0x69c47De9D...This market will resolve based on the highest temperature recorded in the 'Daily Observations' table on Weather Underground, not the figure displayed in the 'Day High & Low' summary section; in the event of any discrepancy between the two, the Daily Observations table shall be the primary resolution source not the Day High & Low section.
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 Aug '26.
The resolution source for this market will be information from Wunderground, specifically the highest temperature recorded for all times on this day for the San Francisco International Airport Station, 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 until the first data point for the following date has been published on the resolution source.
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.Persistent marine layer conditions driven by a stationary low-pressure system in the eastern Pacific and high pressure over the Four Corners have kept San Francisco highs tightly clustered in the mid- to upper-60s°F through mid-August, aligning trader focus on the 68-69°F bin. Onshore flow from the cold California Current and a deep marine layer capped at several thousand feet suppress daytime warming and promote fog or low stratus that limit solar heating, consistent with NOAA climatology showing typical August maxima near 67°F. Recent observations confirm a multi-day streak of 66-68°F readings with minimal model spread for August 21, though subtle subsidence or marine layer thinning could briefly allow 70-71°F. These dynamics explain the heavy weighting toward 66-69°F outcomes while underscoring forecast sensitivity to small changes in boundary-layer moisture or wind patterns.
This market will resolve based on the highest temperature recorded in the 'Daily Observations' table on Weather Underground, not the figure displayed in the 'Day High & Low' summary section; in the event of any discrepancy between the two, the Daily Observations table shall be the primary resolution source not the Day High & Low section.
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 Aug '26.
The resolution source for this market will be information from Wunderground, specifically the highest temperature recorded for all times on this day for the San Francisco International Airport Station, 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 until the first data point for the following date has been published on the resolution source.
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.
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 Aug '26.
The resolution source for this market will be information from Wunderground, specifically the highest temperature recorded for all times on this day for the San Francisco International Airport Station, 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 until the first data point for the following date has been published on the resolution source.
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
$7,586End Date
Aug 21, 2026Market Opened
Aug 19, 2026, 9:57 PM ETResolution Source
https://www.wunderground.com/history/daily/us/ca/san-francisco/KSFOResolver
0x69c47De9D...Persistent marine layer conditions driven by a stationary low-pressure system in the eastern Pacific and high pressure over the Four Corners have kept San Francisco highs tightly clustered in the mid- to upper-60s°F through mid-August, aligning trader focus on the 68-69°F bin. Onshore flow from the cold California Current and a deep marine layer capped at several thousand feet suppress daytime warming and promote fog or low stratus that limit solar heating, consistent with NOAA climatology showing typical August maxima near 67°F. Recent observations confirm a multi-day streak of 66-68°F readings with minimal model spread for August 21, though subtle subsidence or marine layer thinning could briefly allow 70-71°F. These dynamics explain the heavy weighting toward 66-69°F outcomes while underscoring forecast sensitivity to small changes in boundary-layer moisture or wind patterns.
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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