Highest temperature in Shanghai on July 3?

Platform comparison

Market context

The highest temperature recorded at Shanghai Pudong International Airport on 3 July 2026 will determine the outcome of this prediction market, which currently prices the "YES" (30°C or higher) outcome at 0% despite historical data suggesting July is Shanghai’s hottest month. On Polymarket, the frontrunner is the 30°C range at 37%, followed closely by 31°C at 35%, indicating the crowd sees significant upside from the current 0% implied probability. This stark divergence between the abstract real-world likelihood and the on-chain price reflects the conditional token mechanics where USDC liquidity on Polygon is being deployed to bet on temperature thresholds, not the weather event itself.

Historically, Shanghai regularly experiences summer highs exceeding 30°C, often reaching 35°C during sunny spells, with July averaging an 87°F (30.6°C) high at Pudong Airport. Meteorological data confirms this summer is China’s hottest in 60 years since 1961, a catalyst that should push temperatures well above the 30°C threshold and justify the market’s 37% pricing for that outcome over the current 0%[8]. Traders should watch for official announcements from China’s National Meteorological Centre regarding heatwave schedules and any updates to the Wunderground resolution source, as the settlement window ends 2026-07-03T12:00:00Z and depends entirely on the highest temperature recorded for all times on that day. The recent report on China’s record-breaking summer provides a strong factual basis for the 30°C range to resolve as the winner, making the 0% price a clear mispricing relative to the underlying climate reality[8].

Sources: 1 · 2 · 3 · 4 · 5

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

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 Polymarket Legit?. 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'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.