Highest temperature in Shanghai on August 6?

Platform comparison

Market context

Shanghai’s highest temperature at Pudong airport needs only a single afternoon spike to clear the listed range, but the market is pricing **0% YES**, which is hard to reconcile with the forecast set in the public weather models. AccuWeather’s Shanghai August outlook shows a 6 August high of about **89°F/31.7°C**, while other August guides cluster near **31–35°C** for early-month heat; the Met Office is also showing Shanghai running in the **mid-30s°C** with strong daytime warmth. [1][3][9][13]

That makes the current market line look far more pessimistic than the underlying climatology. Shanghai’s August norms are consistently hot and humid, with average highs around **87–88°F (31°C)** and many daily forecasts in the **low- to mid-30s°C** range, so a “highest temperature” contract on the airport station would usually sit above the lowest settlement bands unless cloud, rain, or a sea-breeze suppression cuts the peak. The key comparison here is not whether the day is warm, but whether the airport’s official maximum lands in a range that the market appears to be treating as negligible probability. [1][6][9][16]

Traders should watch the morning-to-afternoon forecast updates, especially any shift in rainfall timing, thunderstorm risk, or typhoon-related cloud cover, because those are the main variables that can shave a few degrees off the daily maximum. The contract resolves from Wunderground’s Shanghai Pudong International Airport Station history page, so the relevant dependency is the station’s recorded max by 12:00 UTC rather than citywide weather sentiment, and early-day observations can still matter if the heat peak arrives later than expected. [2][4][11][14]

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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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.

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 PolyGram trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.