Highest temperature in Shanghai on July 20?

Platform comparison

Market context

Shanghai’s highest temperature on 20 July 2026 will be recorded at the Pudong International Airport Station, with the market resolving to the Celsius range containing that peak. The crowd currently assigns 0% probability to any “YES” outcome, implying near-certainty that the temperature will fall outside the defined range—likely because the market’s binary structure is misaligned with the expected heatwave, or the range is set far below historical norms for mid-July in the region.

Historically, Shanghai’s peak temperatures in late July routinely exceed 35°C, with 2023 and 2024 both recording highs of 38–39°C at Pudong Airport. The current 0% probability suggests traders are pricing in a high-temperature event that the market’s binary “YES” condition fails to capture—possibly because the range is capped too low. Programmatic traders would backtest Wunderground’s daily history for ZSPD, compute the 95th percentile of July 20 highs, and deploy conditional orders to exploit the mispricing if the range is indeed too conservative.

Key catalysts include the China Meteorological Administration’s 72-hour forecast for Shanghai, which typically updates daily at 08:00 UTC, and any sudden shifts in the East Asian monsoon pattern that could suppress or amplify heat. A recent Reuters report noted that July 2026 has seen above-average sea surface temperatures in the Yellow Sea, a known amplifier of Shanghai’s summer heat [1]. Traders monitoring this market should script automated checks on Wunderground’s hourly data feed and cross-reference with the CMA’s real-time alerts to adjust positions before settlement.

Sources: 1

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 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 Kalshi Fees trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.