Highest temperature in Shanghai on August 8?

Platform comparison

Market context

Shanghai’s highest temperature on 8 August will be judged off Weather Underground’s daily observations for Shanghai Pudong International Airport, and the market is currently pricing an extremely cold outcome at **0% YES** despite the city being in its hottest season. That looks disconnected from the underlying climatology: August normals for Shanghai cluster around the low 30s Celsius, with average highs near 32–33°C and many sources showing single-day highs in the mid-30s at this time of year.[2][10][12]

Historical and comparable August readings argue that a high in the relevant range is routine rather than exceptional. Recent Shanghai August data include highs around 34–35°C on several days, while Weather Underground’s own Shanghai history page shows an 8 August reading equivalent to 93°F, which is about 33.9°C.[1][12][16] Against that backdrop, a 0% market-implied probability is materially lower than the seasonal base rate, and it also sits well below the sort of summer heat that outside forecasters have been flagging for early August.[12][16]

The main catalysts are the day’s actual airport observations, especially whether daytime heating peaks late morning or early afternoon before any sea-breeze or shower influence cuts off further gains. Traders should watch the Weather Underground daily observations table rather than the summary high/low box, since the contract resolves to that table if they differ.[1][13] In cross-platform terms, the main comparison point is the gap between this market’s 0% YES pricing and independent weather averages or high-temperature forecasts, which cluster much higher than zero for Shanghai in August.[2][4][12]

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

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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Kalshi vs Polymarket trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.