Recent Met Office forecasts project a 23°C high for London on September 21 under sunny skies and light westerly winds, while other models cluster near 22°C, producing the market's near-even split between those outcomes. High pressure dominates, promoting clear conditions that enhance daytime solar heating, though exact peaks hinge on boundary-layer mixing and any subtle afternoon cloud variations across ensemble runs. Numerical weather prediction uncertainty of roughly 1°C remains typical at this lead time, with resolution differences and parameterization of surface fluxes explaining the spread. Traders weigh these model consensus signals against historical September maxima near 19–20°C as the final observational data approaches.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · UpdatedHighest temperature in London on September 21?
Highest temperature in London on September 21?
22°C 46%
23°C 41%
24°C 9%
21°C 5%
NEW
$21,351 Vol.
NEW
$21,351 Vol.
Sep 21, 2026
18°C or below
<1%
19°C
<1%
20°C
<1%
21°C
5%
22°C
46%
23°C
41%
24°C
9%
25°C
<1%
26°C
<1%
27°C
<1%
28°C or higher
<1%
22°C 46%
23°C 41%
24°C 9%
21°C 5%
NEW
$21,351 Vol.
NEW
$21,351 Vol.
Sep 21, 2026
18°C or below
$166 Vol.
<1%
19°C
$310 Vol.
<1%
20°C
$1,213 Vol.
<1%
21°C
$2,586 Vol.
5%
22°C
$5,512 Vol.
46%
23°C
$5,344 Vol.
41%
24°C
$3,380 Vol.
9%
25°C
$1,944 Vol.
<1%
26°C
$315 Vol.
<1%
27°C
$290 Vol.
<1%
28°C or higher
$291 Vol.
<1%
This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the London City Airport Station in degrees Celsius 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=eglc
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 Metric Units" button until the relevant table displays °C.
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 Celsius (eg, 9°C). 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 Met Office forecasts project a 23°C high for London on September 21 under sunny skies and light westerly winds, while other models cluster near 22°C, producing the market's near-even split between those outcomes. High pressure dominates, promoting clear conditions that enhance daytime solar heating, though exact peaks hinge on boundary-layer mixing and any subtle afternoon cloud variations across ensemble runs. Numerical weather prediction uncertainty of roughly 1°C remains typical at this lead time, with resolution differences and parameterization of surface fluxes explaining the spread. Traders weigh these model consensus signals against historical September maxima near 19–20°C as the final observational data approaches.
This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the London City Airport Station in degrees Celsius 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=eglc
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 Metric Units" button until the relevant table displays °C.
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 Celsius (eg, 9°C). 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=eglc
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 Metric Units" button until the relevant table displays °C.
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 Celsius (eg, 9°C). 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, 12:55 AM ET
Volume
$21,351End Date
Sep 21, 2026Market Opened
Sep 19, 2026, 12:55 AM ETResolution Source
https://www.weather.gov/wrh/timeseries?site=eglcResolver
0x69c47De9D...This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the London City Airport Station in degrees Celsius 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=eglc
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 Metric Units" button until the relevant table displays °C.
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 Celsius (eg, 9°C). 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 Met Office forecasts project a 23°C high for London on September 21 under sunny skies and light westerly winds, while other models cluster near 22°C, producing the market's near-even split between those outcomes. High pressure dominates, promoting clear conditions that enhance daytime solar heating, though exact peaks hinge on boundary-layer mixing and any subtle afternoon cloud variations across ensemble runs. Numerical weather prediction uncertainty of roughly 1°C remains typical at this lead time, with resolution differences and parameterization of surface fluxes explaining the spread. Traders weigh these model consensus signals against historical September maxima near 19–20°C as the final observational data approaches.
This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the London City Airport Station in degrees Celsius 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=eglc
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 Metric Units" button until the relevant table displays °C.
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 Celsius (eg, 9°C). 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=eglc
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 Metric Units" button until the relevant table displays °C.
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 Celsius (eg, 9°C). 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
$21,351End Date
Sep 21, 2026Market Opened
Sep 19, 2026, 12:55 AM ETResolution Source
https://www.weather.gov/wrh/timeseries?site=eglcResolver
0x69c47De9D...Recent Met Office forecasts project a 23°C high for London on September 21 under sunny skies and light westerly winds, while other models cluster near 22°C, producing the market's near-even split between those outcomes. High pressure dominates, promoting clear conditions that enhance daytime solar heating, though exact peaks hinge on boundary-layer mixing and any subtle afternoon cloud variations across ensemble runs. Numerical weather prediction uncertainty of roughly 1°C remains typical at this lead time, with resolution differences and parameterization of surface fluxes explaining the spread. Traders weigh these model consensus signals against historical September maxima near 19–20°C as the final observational data approaches.
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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