Highest temperature in Shanghai on July 13?

Platform comparison

Market context

Shanghai will record its peak daytime temperature at Pudong International Airport on 13 July 2026, with settlement tied to the highest Celsius reading captured by Wunderground for that station. The market currently implies a 0% probability for any specific outcome, yet forecast models converge on a high between 32–34 °C, making the zero-implied stance a clear outlier against empirical consensus [1].

Historical data frames this divergence: July is Shanghai’s hottest month, with average highs at Pudong reaching 87°F (30.6 °C) and summer peaks regularly exceeding 35°C (95°F) under sunny conditions [3][6]. The current 2026 forecast for Pudong lists daily highs from 86° to 97°F (30–36 °C), while real-time modelling for 13 July specifically projects a maximum of 32°C at 14:00 [2][4]. A trader building a programmatic arb would script a Wunderground API poll at 12:00 UTC on 14 July to fetch the day’s max, then compare it against live price bands; the 0% implied probability suggests either a liquidity gap or a mispriced binary, not a genuine expectation of no recordable temperature.

Key catalysts include the 13 July 02:00–14 July 08:00 weather window, where broken clouds and gusts up to 52kt may suppress peak heat, though showers remain possible [4]. Traders should monitor the National Weather Service time-series for ZSPD for real-time deviations from the 32°C model peak, as wind shifts or cloud cover could push the actual max below 30°C, altering settlement [8]. No official announcements are scheduled, but the dependency is purely on the Wunderground daily history feed, which updates automatically once the settlement window closes.

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

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 Polymarket Bot UK. 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 reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.