Highest temperature in Chengdu on July 27?

Platform comparison

Market context

Chengdu’s airport temperature on 27 July will hinge on whether the city delivers a routine hot summer peak or a rain-limited afternoon high. The market’s 0% YES implies traders think the contract’s target band is effectively out of reach, but that is only justified if the day’s maximum at Chengdu Shuangliu stays below the relevant threshold; BBC Weather’s current Chengdu reading shows 24°C with 74% humidity and steady pressure, which is consistent with a warm, cloudy start rather than a locked-in extreme.[1]

Historical context argues against treating a zero price as a strong signal of certainty. July in Chengdu is typically hot and humid, with long-run average highs around 30°C and frequent rain, so a substantial daytime rise is normal when sunshine breaks through between showers.[3] Forecasts for the next two weeks also show a wide range, with temperatures projected between 24°C and 36°C and several rainy days, which means the distribution of possible highs is broad enough that a single wet or clear spell can materially shift the outcome.[2] In cross-platform terms, prediction markets and sportsbook-style pricing often diverge most when weather contracts hinge on a single observation site rather than the citywide feel, so the key comparison is whether outside models or local forecasters are implicitly calling for a capped high that justifies the market’s extreme scepticism.[1][2][3]

Traders should watch the overnight and morning updates from local forecast providers, because any change in rainfall timing, cloud cover, or thunderstorm coverage can alter the eventual airport maximum quickly. The most important dependency is the daytime convective pattern over Sichuan: if showers arrive early, the high can undershoot seasonal norms, but if skies clear by late morning, Chengdu can still climb towards the low 30s Celsius even after a mild start.[2][3] The contract resolves from the Wunderground daily history page for Chengdu Shuangliu International Airport Station, so late-day observations at that station matter more than broader city forecasts.[3]

Sources: 1 · 2 · 3

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 Best Prediction Markets UK. 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'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.

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.