Latest forecast models from sources including the Met Office and Yr.no point to a maximum of 22–23 °C in São Paulo on September 18 under partly cloudy skies and persistent easterly flow. High pressure and southeasterly winds are advecting cooler maritime air while limiting insolation, keeping daytime peaks below the seasonal average. Recent cooler-than-normal conditions in September 2026 have reinforced this pattern, with ensemble guidance showing only modest afternoon warming. The tight clustering of market-implied odds around 22–24 °C reflects remaining uncertainty in exact cloud timing and boundary-layer mixing, which will determine whether the peak edges toward the upper or lower end of that range.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · UpdatedHighest temperature in Sao Paulo on September 18?
Highest temperature in Sao Paulo on September 18?
23°C 35%
24°C 28%
22°C 23%
21°C 11%
NEW
NEW
Sep 18, 2026
15°C or below
<1%
16°C
<1%
17°C
1%
18°C
1%
19°C
2%
20°C
2%
21°C
11%
22°C
23%
23°C
35%
24°C
28%
25°C or higher
6%
23°C 35%
24°C 28%
22°C 23%
21°C 11%
NEW
NEW
Sep 18, 2026
15°C or below
$464 Vol.
<1%
16°C
$334 Vol.
<1%
17°C
$0 Vol.
1%
18°C
$0 Vol.
1%
19°C
$12 Vol.
2%
20°C
$79 Vol.
2%
21°C
$196 Vol.
11%
22°C
$123 Vol.
23%
23°C
$245 Vol.
35%
24°C
$562 Vol.
28%
25°C or higher
$203 Vol.
6%
This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the Sao Paulo-Guarulhos International Airport Station in degrees Celsius on 18 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=sbgr
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.Latest forecast models from sources including the Met Office and Yr.no point to a maximum of 22–23 °C in São Paulo on September 18 under partly cloudy skies and persistent easterly flow. High pressure and southeasterly winds are advecting cooler maritime air while limiting insolation, keeping daytime peaks below the seasonal average. Recent cooler-than-normal conditions in September 2026 have reinforced this pattern, with ensemble guidance showing only modest afternoon warming. The tight clustering of market-implied odds around 22–24 °C reflects remaining uncertainty in exact cloud timing and boundary-layer mixing, which will determine whether the peak edges toward the upper or lower end of that range.
This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the Sao Paulo-Guarulhos International Airport Station in degrees Celsius on 18 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=sbgr
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=sbgr
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 16, 2026, 8:55 AM ET
Volume
$2,214End Date
Sep 18, 2026Market Opened
Sep 16, 2026, 8:55 AM ETResolution Source
https://www.weather.gov/wrh/timeseries?site=sbgrResolver
0x69c47De9D...This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the Sao Paulo-Guarulhos International Airport Station in degrees Celsius on 18 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=sbgr
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.Latest forecast models from sources including the Met Office and Yr.no point to a maximum of 22–23 °C in São Paulo on September 18 under partly cloudy skies and persistent easterly flow. High pressure and southeasterly winds are advecting cooler maritime air while limiting insolation, keeping daytime peaks below the seasonal average. Recent cooler-than-normal conditions in September 2026 have reinforced this pattern, with ensemble guidance showing only modest afternoon warming. The tight clustering of market-implied odds around 22–24 °C reflects remaining uncertainty in exact cloud timing and boundary-layer mixing, which will determine whether the peak edges toward the upper or lower end of that range.
This market will resolve to the temperature range that contains the highest temperature recorded by NOAA at the Sao Paulo-Guarulhos International Airport Station in degrees Celsius on 18 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=sbgr
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=sbgr
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
$2,214End Date
Sep 18, 2026Market Opened
Sep 16, 2026, 8:55 AM ETResolution Source
https://www.weather.gov/wrh/timeseries?site=sbgrResolver
0x69c47De9D...Latest forecast models from sources including the Met Office and Yr.no point to a maximum of 22–23 °C in São Paulo on September 18 under partly cloudy skies and persistent easterly flow. High pressure and southeasterly winds are advecting cooler maritime air while limiting insolation, keeping daytime peaks below the seasonal average. Recent cooler-than-normal conditions in September 2026 have reinforced this pattern, with ensemble guidance showing only modest afternoon warming. The tight clustering of market-implied odds around 22–24 °C reflects remaining uncertainty in exact cloud timing and boundary-layer mixing, which will determine whether the peak edges toward the upper or lower end of that range.
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