Highest temperature in Shanghai on July 21?

Platform comparison

Market context

Shanghai’s highest temperature on 21 July 2026 will be recorded at the Pudong International Airport station and resolved via Wunderground’s daily history, with the market currently pricing any outcome above the lowest range at zero per cent. This reflects the crowd’s view that extreme heat is unlikely, yet historical data shows July in Shanghai routinely sees peaks between 32°C and 38°C, with 2024 reaching 39.1°C at the same station. The 0% YES probability appears misaligned with typical mid-summer climatology, suggesting either a narrow definition of “YES” or a lack of liquidity rather than a genuine forecast of cool conditions.

A programmatic trader would back-test Wunderground’s ZSPD history for the past ten years, extracting daily maxima for 21 July to build a distribution, then overlay real-time forecasts from ECMWF or GFS as the settlement window closes. Key catalysts include the China Meteorological Administration’s weekly heatwave bulletins and any sudden shifts in the East Asian monsoon, which can suppress or amplify temperatures within hours. Recent reporting from the Shanghai Daily notes that July 2025 saw three consecutive days above 37°C, reinforcing that a cool 21 July is statistically anomalous unless a significant rain event or frontal system intervenes before noon UTC on settlement day [1].

Methodology

This page reviews Highest temperature in Shanghai on July 21? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Kalshi Fees, which mirrors the Polymarket order book at 0% fees.

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 Kalshi Fees. 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.

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.