Highest temperature in Shanghai on July 11?

Platform comparison

Market context

Shanghai is bracing for another peak-summer day as the settlement clock ticks toward noon UTC, with the market currently pricing any chance of a sub-30°C high at zero. This 0% YES probability reflects the region’s entrenched heatwave pattern, where July 11 historically sits within a window of sustained highs rarely dipping below 30°C. Over the past 48 hours, ensemble models from global and regional centres have converged on a 31–32°C range for today’s peak, reinforcing the crowd’s view that cooler outcomes are effectively impossible [2].

Historical data frames this certainty: July in Shanghai typically sees daytime temperatures hover above 30°C, often exceeding 35°C, with extreme highs reaching 40°C in some years [4]. The period from 11–20 July specifically averages highs near 30.7°C, while the month’s peak heat arrives later, around July 29, at 88°F (31.1°C) [1][10]. Even in 2025, the high reached 38°C on a comparable date, underscoring how rare a cool July 11 would be [7].

Traders should monitor real-time updates from Wunderground, the official resolution source, as the day progresses, alongside any sudden shifts in cloud cover or precipitation forecasts that could suppress temperatures [2]. While thunderstorms are possible today, heavy rain is forecast primarily for Thursday, leaving Saturday with only a low 30% chance of precipitation and highs likely reaching 84°F (28.9°C) before afternoon breezes intensify [5]. The key dependency remains whether the expected moderate southeast winds (12–18 mph) fail to offset the intense solar radiation, which is gradually increasing through July [1].

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

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

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 Prediction Today. 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.

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.