Highest temperature in Hong Kong on July 1?

Platform comparison

Market context

Hong Kong will record its highest temperature on 1 July 2026, measured in degrees Celsius to one decimal place by the Hong Kong Observatory, with the market currently implying a 0% chance that the temperature will fall within the specified range. This real-world event hinges on the Observatory’s finalized “Absolute Daily Max” data, which becomes official only once published in the relevant “Daily Extract” and cannot resolve until that publication occurs.

Historical July temperatures in Hong Kong typically range from 30°C to 34°C, with the average high reaching 32.2°C, while recent seasonal forecasts for July–September 2026 indicate above-normal temperatures due to ENSO conditions and climate model consensus[1][3]. The 2026 absolute maximum recorded so far is 35.4°C on 30 May[6], suggesting that extreme heat is plausible, yet the 0% implied probability appears to diverge sharply from analyst expectations that July highs will exceed 30°C, a gap also visible when comparing prediction-market odds to lines on competing platforms like Lines.com, which offers nine outcomes for low-temperature contracts[2].

Traders should monitor the Hong Kong Observatory’s daily weather summaries and the release schedule for the “Daily Extract,” as delays in data finalisation could postpone market resolution[4][9]. Recent forecasts also note a potential temperature drop to 13°C by the weekend, though this is unlikely to affect July 1’s peak[7]; the key dependency remains the Observatory’s official publication, which is the sole resolution source and must be awaited before any outcome can be determined.

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

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