Highest temperature in Shanghai on July 4?

Platform comparison

Market context

The highest temperature recorded at Shanghai Pudong International Airport on 4 July 2026 will determine the outcome of this prediction market, with the current crowd-implied probability of a "YES" result sitting at 0%. This contract resolves based on the peak Celsius reading from Wunderground for that specific day, settling when the window closes on 4 July 2026 at 12:00 UTC. On Polymarket, the price reflects a near-zero chance of the event occurring, driven by on-chain mechanics where USDC trades on the Polygon network using conditional tokens to lock in positions.

Historical data frames this 0% probability as highly plausible, given that July is the hottest month in Shanghai with average daily highs reaching 32.5°C (90.5°F) and rarely exceeding 35°C (95°F) [1][4]. Daily high temperatures typically increase from 84°F to 88°F during the month, rarely falling below 75°F [1]. While recent reports noted temperatures in parts of Pudong exceeding 40°C (104°F), such extremes are outliers rather than the norm for early July, making a "YES" outcome statistically improbable unless a severe heatwave strikes [8].

Traders should monitor the Shanghai Meteorological Bureau's daily forecasts and any announcements regarding extreme heat warnings, as these are the primary catalysts for temperature spikes [8]. The current weather outlook for the afternoon suggests a mixture of sunshine and clouds with a possibility of local thunderstorms, which could temporarily lower temperatures [2]. With a 60% probability of precipitation forecast, the likelihood of a record-breaking high temperature diminishes further, reinforcing the market's current pricing [2]. Dependencies include real-time Wunderground updates, which serve as the official resolution source for the contract.

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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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 UK. 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.

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.

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.