Highest temperature in Shanghai on July 9?

Platform comparison

Market context

On 9 July 2026, the Shanghai Pudong International Airport Station will record its peak daytime temperature, which determines the outcome of a prediction market where traders buy YES shares to bet a specific range will occur or NO shares to bet it will not. A YES share pays out if the highest temperature falls within the chosen bracket, while a NO share wins if it lands outside that range. This market currently assigns a 0% probability to the 29°C outcome, suggesting the crowd expects a significantly lower peak.

Historical climate data frames this low probability, as July is Shanghai’s hottest month with average highs near 31°C (87°F), yet summer days regularly exceed 30°C and can reach 35°C under clear skies[5][7]. The current 0% view for 29°C implies traders anticipate either a cooler day due to cloud cover or rain, or perhaps a misalignment with the specific temperature range definition, given that similar markets on Polymarket show higher confidence in ranges like 26°C to 29°C for the lowest temperature[1]. Recent forecasts for the area indicate high clouds and breezy conditions with a predicted 90°F (32°C) peak, which would technically surpass 29°C, yet the market’s zero probability suggests a collective bet on a deviation from this trend[6].

Traders should monitor real-time updates from Wunderground and the National Weather Service for the station ZSPD, as these are the official resolution sources for the highest temperature recorded at any time on that day[3]. Key catalysts include sudden shifts in weather patterns, such as the arrival of light showers or thunderstorms mentioned in recent forecasts, which could suppress the peak temperature below the 29°C threshold[3][6]. While no specific government announcements are pending, the dependency on accurate hourly data means any gap in the Wunderground feed could delay settlement, so watching the live radar for PVG is essential for assessing whether the day will remain hot enough to invalidate the current 0% probability[6].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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 Prediction Market UK. 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.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

Do I need to KYC for this market?

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