Highest temperature in Sao Paulo on May 22?

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Market context

On 22 May, the contract will settle on the day’s highest temperature at São Paulo–Guarulhos International Airport, with the value mapped into a Celsius range from the final Wunderground history page. São Paulo’s climatology in May is mild rather than hot: long-run averages put daytime highs around 22–23°C, with typical rainfall still present but not especially frequent. That makes the upper bands of the market more plausible only if the day turns markedly warmer than normal, while a reading in the low-to-mid 20s remains the base case.

The current 0% yes price looks hard to reconcile with the usual seasonal profile rather than with any special weather signal. Comparable May readings for São Paulo sit around 17.5°C average temperature, with maximums near 22°C and occasional peaks a little above 23°C in local climate datasets. In practical terms, the contract is likely to resolve around the contract’s lower temperature brackets unless a short-lived warm surge lifts the airport station well above climatological norms. For a crypto market, the key point is that USDC-settled pricing can move quickly on late weather updates, but the underlying event is still driven by a single station observation rather than broader city conditions.

Traders should watch the final 24-hour forecast shifts from Brazilian meteorological services and, on the day, the Wunderground history finalisation for SBGR rather than any citywide summary. Rain bands, cloud cover, and wind direction are the main near-term dependencies for the airport reading; in late May, passing frontal systems can cap daytime highs, while warmer northerly flow can briefly push temperatures higher. If there is a broader risk-on or risk-off move in BTC and ETH, it may affect liquidity and spreads on the market, but it does not change the settlement mechanism.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reads Highest temperature in Sao Paulo on May 22? on-chain. Polymarket's quote comes directly from the Polygon order book — the only comparable venue with on-chain settlement. Kalshi (USD, off-chain), Betfair (GBP/EUR, off-chain) and Manifold (play-money) are listed for comparison. Every CTA routes to PolyGram, which mirrors the Polymarket order book directly.

Resolution & payout

Settlement is on-chain via UMA Optimistic Oracle. A proposer posts the outcome with a bond, a two-hour dispute window opens, then the smart contract lifts winning conditional tokens to 1 USDC and sends payments to holders' wallets automatically. No withdrawal fees beyond Polygon gas.

Off-chain venues (Kalshi, Betfair, Smarkets) settle in local fiat through bank-side clearing — faster than SWIFT, slower than on-chain. Manifold pays no real cash.

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.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

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.