Highest temperature in Shanghai on August 9?

Platform comparison

Market context

Shanghai’s top temperature on 9 August is trading like a **favourite to stay below 30°C**, with the crowd at **0% YES** and the market focused on whether the airport station ever prints a proper heat-day reading. The consensus leans to a wet, windy, suppressed-hight outcome: AccuWeather has **85°F/29°C** for Sunday with periods of rain becoming heavy, while Timeanddate and Weather.com.cn are also clustered around the **mid-to-high 20s Celsius** for the day.[3][6][13] That leaves value, if any, on the contrarian case that a brief pre-rain burst or an underestimate in hourly observations pushes the Daily Observations table into a higher range than the headline forecast suggests.[3][6]

Historically, Shanghai in August usually has the profile of a humid summer city rather than a guaranteed scorcher, with typical monthly averages still warm but with plenty of rainfall volatility.[17][18] Comparable August forecast pages for Shanghai show highs commonly in the **low-to-mid 30s°C**, but the spread matters more than the average: when rain bands or thunderstorms arrive, the observed airport maximum can undershoot the broader city forecast by several degrees.[1][11][12] On that basis, the 0% YES price looks like an overstatement if the market is meant to resolve into a temperature range that includes anything from the high-20s to low-30s, but the underdog remains the higher bucket if the day stays sunny longer than expected.[1][8]

The key catalyst is the evolution of the **9 August rain timing**. Forecasts currently point to very high precipitation odds, heavy rain, and gusty onshore flow, all of which can cap daytime heating at Shanghai Pudong International Airport.[3][6][7][11] Traders should watch for any overnight forecast upgrades or downgrades from AccuWeather, Weather.com.cn, and other near-term models, because a later rain arrival would support a higher observed maximum, while earlier and heavier rainfall would lock in the lower range.[3][7][13] The market’s value spot is therefore not the headline “hot August in Shanghai” narrative, but whether the airport station gets even a short window before the rain to print above the consensus band.[3][6]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Shanghai on August 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.

UK Frequently Asked Questions

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 Who Will Win. 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.

Is Polymarket legal in the UK?

Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.

Do I pay tax on prediction market profits in the UK?

UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.

How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.