Recent cold fronts driven by a strong South Atlantic dipole have kept São Paulo under persistent cloud cover, high humidity, and light easterly flow, suppressing daytime heating and producing the rainiest September on record. These stable, moisture-laden conditions limit solar insolation and favor maximum temperatures clustered around 22–23 °C on the 18th, consistent with the near-tied market-implied probabilities. Brief partial clearing could allow brief warming toward 24 °C, while continued overcast would cap readings at 21–22 °C. Updated INMET and GFS model runs over the next 48 hours will clarify whether residual instability or increasing insolation shifts the outcome.
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?
22°C 39%
24°C 25%
23°C 22%
25°C or higher 17%
NEW
NEW
Sep 18, 2026
15°C or below
<1%
16°C
<1%
17°C
2%
18°C
2%
19°C
3%
20°C
10%
21°C
12%
22°C
28%
23°C
29%
24°C
25%
25°C or higher
17%
22°C 39%
24°C 25%
23°C 22%
25°C or higher 17%
NEW
NEW
Sep 18, 2026
15°C or below
$369 Vol.
<1%
16°C
$239 Vol.
<1%
17°C
$0 Vol.
2%
18°C
$0 Vol.
2%
19°C
$0 Vol.
3%
20°C
$0 Vol.
10%
21°C
$3 Vol.
12%
22°C
$6 Vol.
28%
23°C
$6 Vol.
29%
24°C
$5 Vol.
25%
25°C or higher
$0 Vol.
17%
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.Recent cold fronts driven by a strong South Atlantic dipole have kept São Paulo under persistent cloud cover, high humidity, and light easterly flow, suppressing daytime heating and producing the rainiest September on record. These stable, moisture-laden conditions limit solar insolation and favor maximum temperatures clustered around 22–23 °C on the 18th, consistent with the near-tied market-implied probabilities. Brief partial clearing could allow brief warming toward 24 °C, while continued overcast would cap readings at 21–22 °C. Updated INMET and GFS model runs over the next 48 hours will clarify whether residual instability or increasing insolation shifts the outcome.
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
$628End 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.Recent cold fronts driven by a strong South Atlantic dipole have kept São Paulo under persistent cloud cover, high humidity, and light easterly flow, suppressing daytime heating and producing the rainiest September on record. These stable, moisture-laden conditions limit solar insolation and favor maximum temperatures clustered around 22–23 °C on the 18th, consistent with the near-tied market-implied probabilities. Brief partial clearing could allow brief warming toward 24 °C, while continued overcast would cap readings at 21–22 °C. Updated INMET and GFS model runs over the next 48 hours will clarify whether residual instability or increasing insolation shifts the outcome.
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
$628End Date
Sep 18, 2026Market Opened
Sep 16, 2026, 8:55 AM ETResolution Source
https://www.weather.gov/wrh/timeseries?site=sbgrResolver
0x69c47De9D...Recent cold fronts driven by a strong South Atlantic dipole have kept São Paulo under persistent cloud cover, high humidity, and light easterly flow, suppressing daytime heating and producing the rainiest September on record. These stable, moisture-laden conditions limit solar insolation and favor maximum temperatures clustered around 22–23 °C on the 18th, consistent with the near-tied market-implied probabilities. Brief partial clearing could allow brief warming toward 24 °C, while continued overcast would cap readings at 21–22 °C. Updated INMET and GFS model runs over the next 48 hours will clarify whether residual instability or increasing insolation shifts the outcome.
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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