Highest temperature in Shanghai on August 2?

Platform comparison

Market context

Polymarket has this Shanghai airport heat contract marked at **0% YES** today, so the implied price says traders see essentially no chance that the Shanghai Pudong International Airport Station’s top reading on 2 August 2026 lands in the winning temperature band. On Polymarket, that exposure sits in **USDC** on **Polygon**, with the outcome represented by conditional tokens that settle against the Wunderground history page for the airport station, not a citywide average or a general forecast.

For context, Shanghai in August is normally hot enough that high temperatures cluster in the low-to-mid 30s Celsius, and public climate references put average August highs around 32°C to 35°C, with rare spikes closer to 40°C during heatwaves.[1][2][6][8][10] That makes the market’s 0% price a statement about the exact resolution band, not about whether the day will feel hot. Comparable recent Shanghai records show how quickly extremes can arrive: the city reported 39.5°C in August 2025, and local government reporting noted a run of 26 consecutive days above 35°C that month.[2][3][15]

A trader should watch the day’s synoptic setup rather than the calendar alone: inland heat build-up, afternoon thunderstorm timing, cloud cover, and any typhoon-related moisture can change the daily maximum even when the broader month is seasonally warm.[8][10] In practical terms, the most important inputs are the airport’s actual hourly readings before the settlement window closes at 12:00 UTC, because this market resolves from the highest temperature recorded for that station on the day, as published by Wunderground.

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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

FAQ

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.

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.