Highest temperature in Sao Paulo on July 9?

Platform comparison

Market context

The highest temperature recorded at São Paulo-Guarulhos International Airport on 9 July 2026 will determine the outcome of this prediction market, with the current crowd-implied probability of a 23°C reading sitting at 0% YES. Polymarket prices this contract today as a near-certain NO, reflecting the on-chain mechanics where USDC settles conditional tokens on the Polygon network, and traders are effectively betting against an extreme cold anomaly in mid-winter.

Historically, July is São Paulo’s coolest month, with average daily highs ranging from 22°C to 24°C (72°F to 75°F), and typical highs rarely dropping below 18°C [7]. AccuWeather’s 2026 forecast for July shows daily highs between 18°C and 27°C (66°F to 81°F), with an average of 23°C [1]. A 23°C reading is not cold but rather a standard mid-winter high; the 0% probability likely stems from a misinterpretation of the contract’s threshold, as 23°C is well within the normal range, not an outlier.

Traders should monitor the official Wunderground data release for SBGR on 10 July, which will confirm the day’s peak temperature, and watch for any unusual cloud cover or rainfall forecasts that could suppress temperatures below 20°C [9]. While no specific heatwave announcements are pending for early July, the broader Brazilian heat context—such as the 2024 record of 35.9°C in December—suggests that extreme cold is unlikely, making the 0% probability a probable market inefficiency [6]. The settlement window ends 2026-07-09T12:00:00Z, so real-time weather updates from PredictWind or AccuWeather will be critical for final validation [1][9].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Sao Paulo on July 9? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is PolyGram. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like PolyGram trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.