Highest temperature in Chengdu on August 18?

Platform comparison

Market context

On 18 August 2026, the highest temperature recorded at Chengdu Shuangliu International Airport Station will determine this market's settlement. The resolution hinges on Weather Underground's Daily Observations table rather than the Day High & Low summary, a distinction that occasionally produces material differences when stations report sub-hourly readings or corrections. USDC settlement will occur against whichever temperature band captures the peak reading in degrees Celsius on that date.

Chengdu's August climate presents a narrow historical band. Over the past decade, mid-August highs at Shuangliu have ranged between 32–36°C, with extreme outliers rare. The 0% crowd probability suggests traders are pricing in either high confidence in a specific temperature bracket or uncertainty about which range the market's resolution options span. Comparable August dates in 2023 and 2024 saw peaks of 34–35°C; 2022 recorded 36°C. These patterns anchor baseline expectations, though single-day variance of ±2°C remains within normal bounds for the season.

Watch for tropical systems tracking toward central China in early-to-mid August 2026; the China Meteorological Administration's 10-day forecasts, typically issued 8–10 days prior, will signal whether monsoon moisture or high-pressure systems dominate. Funding rates on weather-derivative contracts and spot volatility in commodity markets tied to Chinese agricultural output can serve as leading indicators of atmospheric pattern shifts. Any significant weather advisory issued by CMA in the week preceding 18 August should prompt reassessment of temperature distribution assumptions.

Methodology

Methodologically this overview focuses on on-chain pricing: Polymarket's live mid comes from the Polygon conditional-token order book and settles automatically in USDC. The other three venues — Kalshi, Betfair, Manifold — sit alongside as off-chain reference points so you can see how the contract translates across regulatory and settlement regimes.

Resolution & payout

Settlement is on-chain via UMA Optimistic Oracle. A proposer posts the outcome with a bond, a two-hour dispute window opens, then the smart contract lifts winning conditional tokens to 1 USDC and sends payments to holders' wallets automatically. No withdrawal fees beyond Polygon gas.

Off-chain venues (Kalshi, Betfair, Smarkets) settle in local fiat through bank-side clearing — faster than SWIFT, slower than on-chain. Manifold pays no real cash.

UK Frequently Asked Questions

What are crypto prediction markets?

Crypto prediction markets are on-chain smart contracts where you buy YES or NO shares on a future crypto event (e.g. "BTC above $100k by year-end"). The market price between 0¢ and 100¢ is the implied probability.

Why USDC and not ETH or USDT?

USDC is the Polygon standard — audited reserves (Circle, monthly attestation), deepest order book, low gas costs. ETH volatility would distort probability quotes; USDT has thinner Polygon liquidity than USDC.

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%.