Highest temperature in Beijing on August 17?

Platform comparison

Market context

Beijing's peak temperature on 17 August 2026 will be measured at the Capital International Airport Station and recorded in Weather Underground's Daily Observations table, with settlement tied to whichever temperature range contains that specific reading in degrees Celsius. The distinction between the Daily Observations granular data and the Day High & Low summary section matters operationally—automated resolution systems must query the correct data source to avoid disputes.

Historical August temperatures in Beijing cluster reliably between 25–32°C, with occasional peaks above 33°C during heat waves. The 2023 and 2024 August records show that extreme heat events (above 35°C) occur roughly once per decade in this window, whilst temperatures below 24°C are statistically rare. Current crowd probability at 0% suggests the market may be pricing in a specific temperature threshold that historical data does not support as likely, or traders are waiting for seasonal forecasts before committing capital.

A trader building a programmatic approach would monitor China Meteorological Administration updates and Weather Underground's forecast model adjustments from mid-August onwards. The settlement window closes at 12:00 UTC on 17 August, creating a hard deadline for any last-minute forecast revisions. Conditional order logic could be structured around thresholds: if five-day forecasts shift above 32°C, trigger position entry; if they remain below 28°C, avoid the market entirely. The specificity of the Daily Observations source means verifying that Weather Underground's Beijing station data feeds correctly before market close, as API delays or station maintenance could affect final resolution timing.

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 Polymarket Review UK. 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%.