Highest temperature in Shanghai on July 20?

Platform comparison

Market context

Shanghai is currently experiencing a sweltering heatwave, with the Pudong International Airport station recording a maximum of 38°C today, 20 July 2026. This real-time data starkly contradicts the prediction market’s current crowd-implied probability of 0% for the YES outcome, suggesting a significant mispricing as the settlement window closes within hours. The market, which resolves based on the highest temperature recorded at this specific station, appears to have ignored the immediate meteorological reality unfolding at the airport.

Historical July data for Shanghai typically sees peaks between 34°C and 37°C, making a 38°C reading a notable outlier that aligns with recent extreme heat events in the region. Previous years show that temperatures exceeding 38°C are rare but not impossible during intense summer surges, framing the current 0% probability as an anomaly rather than a rational assessment of risk. Traders comparing cross-platform odds will notice this divergence between the live weather feed and the market’s implied likelihood, creating a clear arbitrage opportunity if the resolution source confirms today’s peak.

The primary catalyst for settlement is the final Wunderground daily report for Shanghai Pudong, which will be published shortly after the current 8 PM UTC timestamp. Traders should monitor the official Wunderground history page for the definitive daily maximum, as any discrepancy between the live Meteoblue reading and the archived Wunderground data could alter the outcome. With rain expected tomorrow and scattered thunderstorms forecast after 8 AM, the current heatwave may be the final high-temperature spike before conditions shift, making today’s 38°C the critical figure for resolution.

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Methodology

We track Highest temperature in Shanghai on July 20? 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.

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.

Do I need to KYC for this market?

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