Highest temperature in Sao Paulo on May 22?

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Market context

The last 24–48 hours have not brought a meaningful warm-up in the São Paulo area, and the airport station is still sitting in the late-autumn pattern that usually keeps daytime maxima moderate. For today’s reading at São Paulo–Guarulhos, the key point is that late May in this part of Brazil is typically far from the summer heat regime: climate normals for São Paulo in May put average highs in the low 20s Celsius, with daily highs often around 22°C and only occasional excursions a little above that.

That historical backdrop matters because the market has been pricing a 0% chance of the highest temperature landing in the upper bands, which is broadly consistent with the climatology. Comparable May days in São Paulo are usually shaped more by cloud cover, cooler nights, and passing frontal systems than by strong heat. Even forecast products for the month point to highs generally in the low-to-mid 20s Celsius rather than any extreme spike, so outcomes in the 20–24°C range look materially more plausible than a significantly hotter print.

The main things to watch are the short-range airport forecast, any incoming cold front, and cloud or rain timing through the afternoon, since the settlement uses the day’s highest observed temperature at the Guarulhos station, not the city centre. If cloud thickens early or a frontal boundary moves through, the peak can be capped well below seasonal averages; if sunshine lasts into early afternoon, the station can still reach the mid-20s Celsius. Traders should keep an eye on Wunderground’s daily history page for the final high once observations are locked in.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

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FAQ

Where can I trade this market with the lowest fees?

On PolyGram, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

What's the difference between YES and NO shares?

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How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.