Highest temperature in Shanghai on July 31?

Platform comparison

Market context

Shanghai’s high at Pudong Airport on 31 July will be the number that decides this contract, not the city-wide record at Xujiahui or any broader municipal average. The market is currently priced at **0% YES**, which is an extreme view for late-July Shanghai: climatology still favours a hot afternoon, with typical July highs in the low-30s °C and late-July daily maxima often around 31–34°C, while individual years can push into the mid-to-high 30s°C.[4][8][14][19]

That is why the current line sits well below the historical risk profile. Shanghai has repeatedly produced prolonged heat in recent summers, including stretches above 35°C and a 12-day heatwave in 2024 that ran from 31 July into mid-August.[2][11] The city’s all-time extremes also show how quickly a benign-looking forecast can turn into a much hotter outcome, with Xujiahui reaching 40.9°C in 2017 and 2022; even though this contract resolves off Pudong Airport, those events matter because they show the region’s capacity for sharp late-summer spikes.[16][17]

For traders, the key catalysts are the same factors that move airport temperatures in the final hours: cloud cover, sea-breeze penetration, precipitation, and any heat advisory or synoptic shift over eastern China. A meaningful cross-platform comparison should also note that sportsbook-style lines, where available, generally track the same weather inputs as prediction markets, but this contract’s 0% crowd price implies either a data mismatch, a stale market, or very strong bearish sentiment relative to the seasonal norm; the most relevant live check is the Pudong Airport history page on Wunderground, since that is the settlement source.[9]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Best Prediction Markets, which mirrors the Polymarket order book directly.

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. 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.