Recent National Weather Service and ensemble forecasts indicate a transition to onshore marine flow over western Washington by September 19, moderating temperatures after several days of offshore warming. Model consensus centers on partly cloudy skies with daytime highs near 70°F at Seattle-Tacoma International Airport, consistent with the late-September climatological average of 69–70°F. Key variables include the strength and timing of the marine push, which can suppress afternoon warming by several degrees, versus residual thermal trough effects that might allow brief clearing and readings in the low 72°F range. This narrow spread around 68–72°F underpins the closely matched market probabilities, with traders weighting the higher likelihood of marine moderation against the potential for slightly warmer interior conditions. Updated model runs and NWS briefings over the next 48 hours will refine these thresholds.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · UpdatedHighest temperature in Seattle on September 19?
Highest temperature in Seattle on September 19?
68-69°F 25%
70-71°F 25%
66-67°F 24%
64-65°F 17%
NEW
NEW
Sep 19, 2026
63°F or below
1%
64-65°F
14%
66-67°F
24%
68-69°F
25%
70-71°F
25%
72-73°F
16%
74-75°F
9%
76-77°F
6%
78-79°F
5%
80-81°F
5%
82°F or higher
4%
68-69°F 25%
70-71°F 25%
66-67°F 24%
64-65°F 17%
NEW
NEW
Sep 19, 2026
63°F or below
$10 Vol.
1%
64-65°F
$117 Vol.
14%
66-67°F
$60 Vol.
24%
68-69°F
$2 Vol.
25%
70-71°F
$0 Vol.
25%
72-73°F
$0 Vol.
16%
74-75°F
$0 Vol.
9%
76-77°F
$0 Vol.
6%
78-79°F
$10 Vol.
5%
80-81°F
$10 Vol.
5%
82°F or higher
$10 Vol.
4%
This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the Seattle-Tacoma International Airport Station in degrees Fahrenheit on 19 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=ksea
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.Recent National Weather Service and ensemble forecasts indicate a transition to onshore marine flow over western Washington by September 19, moderating temperatures after several days of offshore warming. Model consensus centers on partly cloudy skies with daytime highs near 70°F at Seattle-Tacoma International Airport, consistent with the late-September climatological average of 69–70°F. Key variables include the strength and timing of the marine push, which can suppress afternoon warming by several degrees, versus residual thermal trough effects that might allow brief clearing and readings in the low 72°F range. This narrow spread around 68–72°F underpins the closely matched market probabilities, with traders weighting the higher likelihood of marine moderation against the potential for slightly warmer interior conditions. Updated model runs and NWS briefings over the next 48 hours will refine these thresholds.
This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the Seattle-Tacoma International Airport Station in degrees Fahrenheit on 19 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=ksea
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=ksea
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 17, 2026, 7:55 AM ET
Volume
$218End Date
Sep 19, 2026Market Opened
Sep 17, 2026, 7:55 AM ETResolution Source
https://www.weather.gov/wrh/timeseries?site=kseaResolver
0x69c47De9D...This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the Seattle-Tacoma International Airport Station in degrees Fahrenheit on 19 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=ksea
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.Recent National Weather Service and ensemble forecasts indicate a transition to onshore marine flow over western Washington by September 19, moderating temperatures after several days of offshore warming. Model consensus centers on partly cloudy skies with daytime highs near 70°F at Seattle-Tacoma International Airport, consistent with the late-September climatological average of 69–70°F. Key variables include the strength and timing of the marine push, which can suppress afternoon warming by several degrees, versus residual thermal trough effects that might allow brief clearing and readings in the low 72°F range. This narrow spread around 68–72°F underpins the closely matched market probabilities, with traders weighting the higher likelihood of marine moderation against the potential for slightly warmer interior conditions. Updated model runs and NWS briefings over the next 48 hours will refine these thresholds.
This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the Seattle-Tacoma International Airport Station in degrees Fahrenheit on 19 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=ksea
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=ksea
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
$218End Date
Sep 19, 2026Market Opened
Sep 17, 2026, 7:55 AM ETResolution Source
https://www.weather.gov/wrh/timeseries?site=kseaResolver
0x69c47De9D...Recent National Weather Service and ensemble forecasts indicate a transition to onshore marine flow over western Washington by September 19, moderating temperatures after several days of offshore warming. Model consensus centers on partly cloudy skies with daytime highs near 70°F at Seattle-Tacoma International Airport, consistent with the late-September climatological average of 69–70°F. Key variables include the strength and timing of the marine push, which can suppress afternoon warming by several degrees, versus residual thermal trough effects that might allow brief clearing and readings in the low 72°F range. This narrow spread around 68–72°F underpins the closely matched market probabilities, with traders weighting the higher likelihood of marine moderation against the potential for slightly warmer interior conditions. Updated model runs and NWS briefings over the next 48 hours will refine these thresholds.
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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