Highest temperature in Shanghai on August 21?

Platform comparison

Market context

Shanghai's highest temperature on 21 August 2026 will be measured at Pudong International Airport Station and recorded in Weather Underground's Daily Observations table, with resolution tied to the specific hourly reading rather than the rounded summary figure. The settlement window closes at midday UTC on that date, creating a narrow window for final data verification before the market locks.

Historical August temperatures in Shanghai cluster between 32–35°C as daily highs, with extreme readings occasionally reaching 37–38°C during heat waves driven by Pacific anticyclones. The 0% crowd probability suggests traders are either awaiting clearer seasonal forecasts or treating this as a calibration exercise for a market with genuine uncertainty. Comparable markets on Shanghai summer temperatures typically see meaningful probability mass distributed across the 32–36°C bands, with tail outcomes (sub-30°C or above 38°C) receiving minimal backing. Current crowd positioning warrants scrutiny: a flat 0% reading often indicates low liquidity or an early-stage market awaiting participant engagement rather than genuine confidence in a specific outcome.

Traders monitoring this market should track China Meteorological Administration seasonal outlooks and any El Niño or La Niña phase shifts announced in the coming months, as these drive regional heat patterns. Programmatic approaches would benefit from integrating Weather Underground's API directly rather than relying on manual daily checks, allowing conditional order triggers tied to forecast updates. The specificity of the Daily Observations resolution source—rather than the Day High & Low summary—means automated systems should validate against the correct table structure to avoid settlement disputes.

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Polymarket Review UK, which mirrors the Polymarket order book directly.

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 Polymarket Review 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%.