Ensemble forecasts from leading models like ECMWF and GFS drive trader consensus toward 27-28°C as the most likely highest temperature in Sao Paulo on March 20, reflecting a narrow spread amid persistent autumn warmth influenced by fading El Niño patterns. INMET's latest guidance highlights peak afternoon heat around 2-4 PM local time, with urban heat island effects in the densely built metropolis pushing readings higher, while southerly sea breezes and variable cloud cover create the razor-thin differentiation between 27°C and 28°C outcomes. Historical March maxima average 28°C, but recent model runs show slight cooling from high-pressure ridging breakdown, tempering odds for 29°C or above. Traders eye tomorrow's 12Z updates for potential shifts.
Experimental AI-generated summary referencing Polymarket data · UpdatedHighest temperature in Sao Paulo on March 20?
Highest temperature in Sao Paulo on March 20?
27°C 30%
28°C 26%
26°C 19%
29°C 14%
23°C or below
2%
24°C
2%
25°C
2%
26°C
19%
27°C
30%
28°C
26%
29°C
14%
30°C
8%
31°C
2%
32°C
2%
33°C or higher
2%
27°C 30%
28°C 26%
26°C 19%
29°C 14%
23°C or below
2%
24°C
2%
25°C
2%
26°C
19%
27°C
30%
28°C
26%
29°C
14%
30°C
8%
31°C
2%
32°C
2%
33°C or higher
2%
The resolution source for this market will be information from Wunderground, specifically the highest temperature recorded for all times on this day by the Forecast for the Sao Paulo-Guarulhos International Airport Station once information is finalized, available here: https://www.wunderground.com/history/daily/br/guarulhos/SBGR.
To toggle between Fahrenheit and Celsius, click the gear icon next to the search bar and switch the Temperature setting between °F and °C.
This market can not resolve to "Yes" until all data for this date has been finalized.
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.
Any revisions to temperatures recorded after data is finalized for this market's timeframe will not be considered for this market's resolution.
Market Opened: Mar 16, 2026, 6:01 AM ET
Resolution Source
https://www.wunderground.com/history/daily/br/guarulhos/SBGRResolver
0x69c47De9D...Resolution Source
https://www.wunderground.com/history/daily/br/guarulhos/SBGRResolver
0x69c47De9D...Ensemble forecasts from leading models like ECMWF and GFS drive trader consensus toward 27-28°C as the most likely highest temperature in Sao Paulo on March 20, reflecting a narrow spread amid persistent autumn warmth influenced by fading El Niño patterns. INMET's latest guidance highlights peak afternoon heat around 2-4 PM local time, with urban heat island effects in the densely built metropolis pushing readings higher, while southerly sea breezes and variable cloud cover create the razor-thin differentiation between 27°C and 28°C outcomes. Historical March maxima average 28°C, but recent model runs show slight cooling from high-pressure ridging breakdown, tempering odds for 29°C or above. Traders eye tomorrow's 12Z updates for potential shifts.
Experimental AI-generated summary referencing Polymarket data · Updated
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