Highest temperature in Shanghai on July 21?

Platform comparison

Market context

Shanghai is currently experiencing a heatwave on 21 July 2026, with the Shanghai Pudong International Airport Station recording a maximum temperature of 38°C today. This real-time data directly contradicts the market’s current crowd-implied probability of 0% for the highest temperature falling within lower ranges, suggesting the market may be mispricing the immediate likelihood of extreme heat. The settlement window closes at 12:00 UTC, meaning the final reading for this day is still pending but the morning peak has already surpassed typical July averages.

Historical July data for Shanghai shows that temperatures exceeding 37°C are frequent during heatwaves, with 38°C being a common peak in recent years rather than an outlier. The current 0% probability implies the crowd expects a significantly cooler day, which diverges sharply from the observed meteorological reality and comparable cases from the last decade where similar cloud cover and wind conditions still produced highs near 38°C. This discrepancy frames the contract as a potential arbitrage opportunity where the implied probability fails to align with the hard data from the resolution source.

Traders should monitor the final hourly updates from Wunderground before the 12:00 UTC settlement cutoff, as the afternoon temperature trajectory could either confirm the morning peak or push the daily maximum higher. No specific weather announcements or schedule changes are currently pending that would alter the forecast, but the immediate dependency is the station’s final logged value for the day. The divergence between the live 38°C reading and the 0% market odds highlights a significant gap between sportsbook-style intuition and the factual weather record available on the resolution platform.

Sources: 1

Methodology

We track Highest temperature in Shanghai on July 21? 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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

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.

Do I need to KYC for this market?

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