Highest temperature in Shanghai on May 29?

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Market context

Shanghai's maximum temperature on 29 May 2026 will be recorded at Pudong International Airport Station and resolved against Wunderground historical data. The crowd currently assigns zero probability to any outcome occurring, suggesting either technical confusion or genuine uncertainty about which temperature band will materialise on that specific date.

Late May in Shanghai typically sits in the warm-to-hot range, with historical averages around 28–32°C for daily highs during this period. The city's subtropical climate produces consistent patterns: May temperatures rarely dip below 25°C or exceed 37°C at the airport station. Previous years show clustering around 30–33°C as the modal outcome, with occasional spikes into the mid-30s during early heat waves. The zero probability reading appears disconnected from seasonal norms, suggesting traders may be waiting for resolution bands to be formally specified before committing capital.

The key variable for late May is whether an early summer heat event develops across eastern China. Meteorological forecasts become reliable only within 10–14 days of the target date, so traders should monitor China Meteorological Administration updates from mid-May onwards. Tropical systems occasionally influence Shanghai's weather in late May, though they typically bring rain rather than extreme heat. The settlement window closes at noon UTC on 29 May, creating a tight window for final data confirmation. Until specific temperature ranges are published by the market operator, the zero probability likely reflects absent price discovery rather than genuine consensus that no temperature will be recorded.

Methodology

We track Highest temperature in Shanghai on May 29? 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 Who Will Win, 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?

Who Will Win 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 Who Will Win?

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