Highest temperature in Chengdu on August 4?

Platform comparison

Market context

Chengdu’s airport is sitting in a market that implies **0% YES**, so the field is effectively pricing in no chance of a qualifying high on the winning side and treating the listed Celsius bands as the real battleground. That makes the favourite the cluster of mid-30s outcomes rather than any outlier heat spike, with the crowd consensus centred on **34°C** and **35°C** in the Polymarket book[15].

That pricing fits the summer pattern for Chengdu, where August is typically hot, humid and rain-affected. Forecast and climate pages for 4 August point to highs around **31–32°C** with patchy rain, while broader August guides put daytime maxima in the **30–34°C** range and note frequent rainfall and high humidity[1][2][3][5][7]. On that framing, **34°C** looks like the favourite, **35°C** is the main underdog with some appeal if sunshine breaks through, and the more contrarian angle is that convection or cloud cover keeps the airport below the consensus band and hands value to the lower 30s outcomes[15].

For catalysts, traders should watch the same-day evolution of cloud cover, thunderstorm timing and whether rain arrives early enough to cap heating; in this market, the day’s top reading can be set by a short afternoon spike before showers move in. The settlement source is the Wunderground history page for Chengdu Shuangliu International Airport, and the market rules say revisions to readings are considered until the first datapoint for the following date is published, so late updates matter[15]. Reuters coverage on China’s summer weather has repeatedly highlighted the volatility of heat-and-rain setups across inland cities, which is the key dependency here: if the afternoon breaks warmer and drier than forecast, the upside is a move from 32–33°C into the 34–35°C band; if not, the under remains the cleaner contrarian case[15].

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 Who Will Win 2026. 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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Who Will Win 2026 trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.