Highest temperature in Chengdu on August 20?

Platform comparison

Market context

Chengdu's daily maximum temperature on 20 August 2026 will be measured at Shuangliu International Airport Station, with resolution determined by the Daily Observations table on Weather Underground rather than summary figures. The market currently shows 0% implied probability across all temperature ranges, suggesting either insufficient liquidity or a technical issue in pricing, as historical August conditions in Chengdu consistently produce measurable highs well above freezing.

Chengdu experiences a humid subtropical climate with August typically among its warmest months. Historical data from the past decade shows August highs ranging between 28–35°C, with extreme readings occasionally exceeding 37°C during heat waves. The 0% crowd probability appears misaligned with seasonal norms, indicating traders may be awaiting clarification on specific temperature thresholds or experiencing platform-wide liquidity constraints. No major weather forecasting services currently publish predictions two years in advance, making early-stage trading largely speculative.

Traders should monitor China Meteorological Administration seasonal outlooks as 2026 approaches, particularly any El Niño or La Niña signals that could influence summer heat patterns across central China. The resolution methodology—prioritising Weather Underground's Daily Observations table over summary data—creates a technical dependency worth verifying before committing capital. Cross-platform comparison shows minimal activity on equivalent contracts, suggesting this market remains in discovery phase with pricing likely to shift substantially once forecast windows narrow to within 10–14 days of the settlement 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 Best Prediction Markets 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.

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.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

What are the best prediction markets for UK traders in 2026?

For UKGC-regulated markets: Betfair Exchange (sports, politics) and Smarkets (sports, politics, lower commission than Betfair). For broader global event prediction: Polymarket (deepest liquidity, 0% fee, USDC settlement). For US-regulated option: Kalshi (USD, limited UK payment options). Most serious UK traders use a combination of Betfair for regulated sports and Polymarket for broader markets.