Highest temperature in Guangzhou on July 27?

Platform comparison

Market context

Guangzhou Baiyun International Airport is in the middle of a long, hot, humid summer window, and the relevant settlement is the day’s *highest* airport temperature in Celsius rather than the city-wide average. Seasonal guides place Guangzhou’s July highs around the mid-30s, with frequent rain and thunderstorms but also plenty of hot, muggy spells that can still produce an upper-30s reading at the airport station.[2][3]

That is why a 0% YES implied probability looks well below the climatological backdrop: the market is only a win if the reading falls into the specific range that matches the contract’s YES threshold, so traders have to judge not just whether Guangzhou is hot, but whether the airport’s official maximum clears that exact band. Long-range forecasts for the coming days already show highs near 37°C and unstable conditions, which supports a hot base case but leaves room for cloud cover or rain to cap the daily maximum below the highest bins if timing shifts.[1]

The main catalysts are the local convective pattern, any thunderstorm complexes, and the precise timing of sunbreaks versus rainfall before the 12:00Z settlement window, because those factors can materially change the airport maximum even when the broader city remains oppressive. In cross-platform terms, sportsbook-style temperature lines would normally price a broad range around the low-to-mid 30s for late July, while prediction markets on a narrow range contract can diverge sharply if the implied band is far out on the tail; with no visible published analyst consensus for this exact contract, the practical benchmark is the seasonal forecast rather than a named street forecast.[1][2][3]

Sources: 1 · 2 · 3

Methodology

We track Highest temperature in Guangzhou on July 27? 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 Best Prediction Markets 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.

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.

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.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.