Highest temperature in Sao Paulo on May 22?

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Active sub-markets

Market context

On 22 May 2026, the highest temperature recorded at São Paulo-Guarulhos International Airport will fall into one of several defined ranges. The settlement mechanism pulls data from Weather Underground's historical records for that specific station, converting to Celsius and resolving once the day's peak is finalised. Polymarket currently prices all temperature ranges at 0% YES, reflecting either insufficient liquidity or genuine uncertainty about which bracket will capture the actual high—a common state for weather contracts weeks in advance where conditional token pricing hasn't yet crystallised around a consensus forecast.

May represents late autumn in São Paulo, when daily highs typically range between 24–28°C, though the airport's microclimate and measurement protocols can produce variation. Historical May data from Guarulhos shows occasional peaks exceeding 30°C during warm spells, but sustained heat above 32°C remains uncommon for the month. The 0% pricing across all ranges suggests the market awaits either clearer seasonal forecasts or sufficient trader participation to establish meaningful price discovery. Comparable weather markets on Polymarket tend to see activity concentrate in the final week before settlement as deterministic forecasts become available.

Traders should monitor Brazil's meteorological forecasts from INMET (Instituto Nacional de Meteorologia) as May approaches, particularly any alerts for heat waves or cold fronts that could shift the typical range. The Southern Hemisphere's autumn progression and any anomalous atmospheric patterns—tracked through NOAA's Southern Oscillation Index for ENSO activity—may influence conditions. Settlement closes at 12:00 UTC on 22 May, giving traders a narrow window to react to actual morning conditions before the day's peak temperature is recorded.

Methodology

We track Highest temperature in Sao Paulo on May 22? on the five venues with material liquidity for prediction markets. Live odds come from the Polymarket Polygon order book — the only source that ships real-time data under an open licence. For Kalshi, Betfair and Manifold we list platform attributes (fee, KYC, settlement, payment) instead of fabricated odds, because their APIs use non-comparable contract definitions.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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.

Is this market available outside the US?

PolyGram is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

What does it cost to trade on PolyGram?

Zero. PolyGram routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, PolyGram triggers a quick verification flow that finishes in minutes.

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.