Highest temperature in Chengdu on August 17?

Platform comparison

Market context

Chengdu will record its highest temperature on 17 August 2026 at Shuangliu International Airport Station, measured via the Daily Observations table on Weather Underground rather than the Day High & Low summary. The market currently prices all temperature ranges at 0% YES on Polygon, reflecting either minimal trading volume or genuine uncertainty about which bracket will contain the day's peak reading. Settlement occurs at 12:00 UTC on that date, giving traders a fixed window to monitor actual conditions against the predetermined temperature bands.

Chengdu's August climate presents a stable baseline for comparison. Historical data from the past decade shows mid-August highs typically ranging between 32–36°C, with extreme readings occasionally exceeding 37°C during particularly intense heatwaves. The 2022 summer saw sustained temperatures above 40°C across Sichuan Province, though Chengdu itself remained marginally cooler. These precedents suggest the market's current flat probability distribution may underweight the likelihood of moderate-to-warm outcomes (32–35°C range) that dominate most years.

Traders should monitor China Meteorological Administration forecasts released in early August 2026, which typically provide 10-day outlooks with reasonable accuracy for regional temperature bands. La Niña or El Niño conditions active during mid-2026 will influence whether the monsoon season delivers cooler, wetter air or allows high-pressure systems to dominate. Urban heat island effects at the airport station itself—a concrete-heavy environment—tend to amplify readings relative to surrounding rural areas, a factor often overlooked in seasonal comparisons. Weather Underground's data feed occasionally experiences delays or corrections within 48 hours post-settlement, so traders should verify final readings against official Chinese meteorological records.

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 Alternative 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%.