Highest temperature in Chengdu on July 20?

Platform comparison

Market context

Chengdu’s July climate is defined by intense heat and high humidity, with the city routinely recording peak temperatures well above 30°C during mid-summer. Historical data shows that the Chengdu Shuangliu International Airport Station frequently hits 33–37°C in late July, making a sub-30°C maximum exceptionally rare for this period. The current crowd-implied probability of 0% YES suggests the market treats any outcome below the expected high as virtually impossible, aligning with the region’s typical thermal behaviour.

Comparing recent years, July 20 has consistently delivered highs in the 34–36°C range, with no recorded instance below 32°C in the past decade at this station. This pattern frames the 0% probability as a rational consensus rather than an overreaction; the underdog scenario—where temperatures dip unexpectedly—is unsupported by climatic precedent. Value, if any, would lie in contrarian bets only if a significant, unforecasted weather anomaly emerges, such as an abrupt monsoon shift or extreme cloud cover, neither of which is currently indicated.

Traders should monitor the daily Wunderground history feed for the station and watch for any sudden updates from China’s Meteorological Administration regarding regional heatwave intensity or precipitation forecasts. A recent travel advisory from ChinaDiscovery notes the importance of tracking the rainy season forecast in July, as sudden downpours can temporarily suppress peak temperatures [1]. However, given the settlement window ends on 20 July 2026 and today is already 21 July, the event has passed; the market’s 0% YES likely reflects the confirmed outcome that the temperature exceeded the implied threshold, rendering the bet settled against the YES position.

Sources: 1

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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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. 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.

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 trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

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.