Highest temperature in Shanghai on August 18?

Platform comparison

Market context

On 18 August 2026, Shanghai will record a daily high temperature at Pudong International Airport Station. This market asks traders to predict which temperature range will contain that peak reading, measured in degrees Celsius. In prediction markets, a YES share pays out if the event occurs as specified; a NO share pays out if it does not. Here, traders are essentially betting on whether the day's maximum temperature falls within a particular band—say, 32–34°C or 35–37°C—rather than predicting a single figure.

Shanghai's August climate is remarkably consistent. Historical data from the past two decades shows daily highs in mid-August cluster tightly between 32 and 35°C, with occasional spikes to 36°C during heat waves. The city's subtropical monsoon pattern means late summer is reliably warm and humid; extreme outliers above 38°C or below 30°C are exceptionally rare in this window. The 0% crowd probability currently assigned suggests traders expect a temperature outcome outside the highest ranges being offered, or that the market's range definitions do not align with typical August conditions.

Weather Underground's Daily Observations table, the specified resolution source, records readings taken at regular intervals throughout the day at the airport station. Traders should monitor China Meteorological Administration forecasts in the weeks preceding mid-August 2026, as any unusual pressure systems or typhoon activity affecting eastern China could shift temperatures materially. The settlement window closes at midday UTC on 18 August, meaning final resolution depends on observations recorded up to that point.

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.

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 Prediction Market UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

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%.