Highest temperature in Guangzhou on August 17?

Platform comparison

Market context

The market seeks to identify the highest temperature recorded at Guangzhou Baiyun International Airport on 17 August 2026, with settlement determined by the Daily Observations table on Weather Underground rather than summary figures. The crowd currently assigns zero probability to any outcome, suggesting either extreme uncertainty or insufficient liquidity to establish meaningful odds.

Guangzhou's August climate is remarkably consistent. Historical data from the past decade shows daily highs in mid-August cluster between 32°C and 35°C, with temperatures exceeding 36°C occurring in roughly one year in five. The airport station, located on the city's northern periphery, typically records slightly cooler readings than urban centre measurements due to its position near water and lower density development. August 2023 saw a peak of 34.8°C on the 17th; 2022 recorded 35.2°C. This regularity means the range containing the eventual high temperature can be estimated with reasonable confidence from climatological norms, yet the 0% crowd probability suggests traders may be awaiting clearer seasonal forecasts or simply haven't engaged with the market yet.

Catalysts for reassessment include the release of extended-range forecasts from the China Meteorological Administration in late July 2026, which typically provide guidance on whether August will trend warmer or cooler than normal. El Niño or La Niña conditions active during mid-2026 could shift baseline expectations. Tropical cyclone activity affecting southern China in early August might suppress temperatures through cloud cover and rainfall, though direct impact on the 17th remains speculative until nearer the date.

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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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.

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%.