Highest temperature in Chengdu on July 20?

Platform comparison

Market context

Chengdu is entering its peak summer heatwave on 20 July 2026, with the city historically recording maximum temperatures between 31°C and 35°C during this period. The market on Polymarket.com.se currently prices the YES outcome at 0%, implying the crowd believes the highest temperature will fall outside the implied range, likely due to expectations of rain or cloud cover typical of the region’s rainy season.

Historical data shows July in Chengdu averages a maximum of 31°C (88°F), with 50% of days experiencing moderate rainfall and 75% relative humidity, creating boisterous, humid conditions that often suppress peak temperatures [1]. While heatwaves can push temperatures above 35°C, the frequent precipitation and cloud cover—averaging 8.7 hours of sunshine daily—make extreme highs less certain, supporting the current low probability assigned to the YES outcome [1].

Traders should monitor the daily weather forecast from Wunderground for the Chengdu Shuangliu International Airport Station, as real-time updates on precipitation and cloud cover will directly impact the settlement temperature [1]. The market resolves based on the highest recorded temperature for that day in Celsius, with settlement occurring after 2026-07-20T12:00:00Z, so any sudden shifts in forecasted rain or humidity before that cutoff could alter on-chain conditional token valuations in USDC on Polygon.

Sources: 1 · 2

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 PolyGram. 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'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 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.