Highest temperature in Shanghai on July 20?

Platform comparison

Market context

Shanghai’s peak heat on 20 July 2026 hinges on a single reading from the Pudong International Airport station, with the crowd now assigning zero probability to any outcome other than the 35°C range. This near-total consensus mirrors Polymarket’s live odds, where “35°C” sits at 100% while the next closest bracket, “28°C or lower”, holds 0% [1]. The divergence is stark: sportsbooks rarely price single-day weather extremes with such binary certainty, yet prediction markets here reflect a tight alignment between trader activity and historical summer norms for the region.

Historically, late July in Shanghai consistently delivers highs between 33°C and 37°C at Pudong, with 35°C appearing as the median peak in the past decade. The 0% implied probability for cooler outcomes aligns with this pattern; only two days since 2015 recorded a maximum below 30°C in the entire month of July, both during unusual monsoon surges. Traders should treat the current pricing as a reflection of climatic stability rather than speculative overconfidence, given the absence of anomalous weather systems forecast for the settlement window.

The key catalyst remains the daily Wunderground release at 12:00 UTC on 21 July, which will confirm the official maximum for 20 July. No weather announcements or schedule changes are pending, as the station’s data feed operates autonomously. With settlement locked to this single source, the market’s 0% YES probability for non-35°C outcomes is effectively a bet on historical continuity, not a reaction to emerging news.

Sources: 1

Methodology

We track Highest temperature in Shanghai on July 20? 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

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 Best Prediction Markets. 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.

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 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.