Highest temperature in Guangzhou on August 21?

Platform comparison

Market context

Guangzhou will experience peak summer heat on 21 August 2026, with the settlement hinging on the precise daily maximum temperature recorded at Baiyun International Airport Station. The market currently shows zero crowd conviction, suggesting either extreme uncertainty about the specific temperature band or insufficient trader participation at this early stage. Resolution will depend on Weather Underground's Daily Observations table rather than summary figures, a distinction that occasionally produces material differences in recorded highs during volatile weather patterns.

August represents Guangzhou's hottest month climatologically, with historical daily maxima typically ranging between 32–35°C, though readings above 36°C occur in roughly one year per decade during particularly intense heat waves. The 2013 heat wave pushed temperatures to 38.9°C, whilst more recent summers have remained within the 33–35°C band. Current zero probability across all temperature ranges suggests the market has attracted minimal liquidity rather than reflecting genuine consensus that no specific outcome will occur—a common pattern for niche weather contracts with extended settlement windows.

Traders should monitor China Meteorological Administration forecasts from mid-August and any tropical cyclone activity in the South China Sea, which occasionally moderates peak temperatures through increased cloud cover. Seasonal monsoon patterns and urban heat island effects around the airport station merit attention; recent urbanisation near Baiyun has produced marginal warming trends in some years. Cross-platform comparison reveals prediction markets have substantially lower engagement on this contract than comparable temperature markets for major Chinese cities, indicating potential mispricing if regional weather patterns diverge from climatological norms.

Methodology

We track Highest temperature in Guangzhou on August 21? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

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 Kalshi vs Polymarket. 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.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

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.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.