Current National Weather Service guidance and ensemble models project a high near 65°F for San Francisco on September 21, driven by a cutoff low positioned over the Central Coast that is enhancing onshore flow and marine layer development. This setup increases cloud cover and suppresses afternoon warming relative to the seasonal average high of about 71°F, keeping temperatures in the mid-60s rather than the upper 60s or low 70s that would require stronger offshore or downslope influences. Trader consensus on the 66-67°F bin reflects the narrow range of likely outcomes under these stable synoptic conditions, with modest probabilities for adjacent bins accounting for minor model spread in boundary-layer mixing or wind strength. Updated short-range guidance through the weekend will refine the exact peak as the low shifts.
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 September 21?
Highest temperature in San Francisco on September 21?
66-67°F 36%
68-69°F 32%
64-65°F 19%
70-71°F 17%
NEW
NEW
Sep 21, 2026
61°F or below
5%
62-63°F
5%
64-65°F
19%
66-67°F
36%
68-69°F
32%
70-71°F
20%
72-73°F
10%
74-75°F
13%
76-77°F
4%
78-79°F
2%
80°F or higher
3%
66-67°F 36%
68-69°F 32%
64-65°F 19%
70-71°F 17%
NEW
NEW
Sep 21, 2026
61°F or below
$10 Vol.
5%
62-63°F
$11 Vol.
5%
64-65°F
$101 Vol.
19%
66-67°F
$195 Vol.
36%
68-69°F
$277 Vol.
32%
70-71°F
$304 Vol.
20%
72-73°F
$6 Vol.
10%
74-75°F
$10 Vol.
13%
76-77°F
$10 Vol.
4%
78-79°F
$10 Vol.
2%
80°F or higher
$10 Vol.
3%
This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the San Francisco International Airport Station in degrees Fahrenheit on 21 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=ksfo
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.Current National Weather Service guidance and ensemble models project a high near 65°F for San Francisco on September 21, driven by a cutoff low positioned over the Central Coast that is enhancing onshore flow and marine layer development. This setup increases cloud cover and suppresses afternoon warming relative to the seasonal average high of about 71°F, keeping temperatures in the mid-60s rather than the upper 60s or low 70s that would require stronger offshore or downslope influences. Trader consensus on the 66-67°F bin reflects the narrow range of likely outcomes under these stable synoptic conditions, with modest probabilities for adjacent bins accounting for minor model spread in boundary-layer mixing or wind strength. Updated short-range guidance through the weekend will refine the exact peak as the low shifts.
This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the San Francisco International Airport Station in degrees Fahrenheit on 21 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=ksfo
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=ksfo
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 19, 2026, 7:56 AM ET
Volume
$945End Date
Sep 21, 2026Market Opened
Sep 19, 2026, 7:56 AM ETResolution Source
https://www.weather.gov/wrh/timeseries?site=ksfoResolver
0x69c47De9D...This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the San Francisco International Airport Station in degrees Fahrenheit on 21 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=ksfo
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.Current National Weather Service guidance and ensemble models project a high near 65°F for San Francisco on September 21, driven by a cutoff low positioned over the Central Coast that is enhancing onshore flow and marine layer development. This setup increases cloud cover and suppresses afternoon warming relative to the seasonal average high of about 71°F, keeping temperatures in the mid-60s rather than the upper 60s or low 70s that would require stronger offshore or downslope influences. Trader consensus on the 66-67°F bin reflects the narrow range of likely outcomes under these stable synoptic conditions, with modest probabilities for adjacent bins accounting for minor model spread in boundary-layer mixing or wind strength. Updated short-range guidance through the weekend will refine the exact peak as the low shifts.
This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the San Francisco International Airport Station in degrees Fahrenheit on 21 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=ksfo
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=ksfo
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
$945End Date
Sep 21, 2026Market Opened
Sep 19, 2026, 7:56 AM ETResolution Source
https://www.weather.gov/wrh/timeseries?site=ksfoResolver
0x69c47De9D...Current National Weather Service guidance and ensemble models project a high near 65°F for San Francisco on September 21, driven by a cutoff low positioned over the Central Coast that is enhancing onshore flow and marine layer development. This setup increases cloud cover and suppresses afternoon warming relative to the seasonal average high of about 71°F, keeping temperatures in the mid-60s rather than the upper 60s or low 70s that would require stronger offshore or downslope influences. Trader consensus on the 66-67°F bin reflects the narrow range of likely outcomes under these stable synoptic conditions, with modest probabilities for adjacent bins accounting for minor model spread in boundary-layer mixing or wind strength. Updated short-range guidance through the weekend will refine the exact peak as the low shifts.
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