Highest temperature in Hong Kong on July 18?

Platform comparison

Market context

On 18 July 2026, the Hong Kong Observatory will record the day's highest temperature in degrees Celsius. The market currently prices at 0% YES across all temperature bands, reflecting the settlement window's closure at midday UTC—well before Hong Kong's typical afternoon peak. This timing mismatch means the contract cannot resolve until the Observatory publishes its daily extract, creating a gap between when the physical event occurs and when traders can claim conditional tokens on Polygon.

Hong Kong's July temperatures cluster tightly around 32–34°C on average, with absolute daily maxima rarely exceeding 36°C. Historical data from the Observatory shows that extreme heat days—those reaching 37°C or above—occur roughly once per decade in mid-July, whilst readings below 30°C are exceptionally rare. The 0% pricing reflects not scepticism about heat itself but rather the technical constraint: no outcome can resolve until official data arrives, making all positions illiquid until publication.

Traders monitoring this contract should track the Observatory's publication schedule for the daily extract, typically released within 48 hours of the observation date. Broader catalysts include the Asian summer monsoon's intensity in early July, which influences whether high-pressure systems dominate the region. Recent patterns from June 2024 and 2025 showed occasional spikes above 35°C during similar periods, though predicting specific daily maxima remains inherently uncertain. The USDC settlement will depend entirely on the Observatory's recorded figure to one decimal place, with no adjustment for methodology changes.

Methodology

We track Highest temperature in Hong Kong on July 18? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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.

Do I need to KYC for this market?

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