Highest temperature in Hong Kong on July 21?

Platform comparison

Market context

Hong Kong will record its highest temperature on 21 July 2026, with the Hong Kong Observatory publishing the absolute daily maximum in degrees Celsius to one decimal place. The prediction market currently shows a 0% implied probability for the “YES” outcome, suggesting traders believe the event is impossible or that the contract structure misaligns with the resolution criteria.

Historically, Hong Kong’s July highs typically range between 31°C and 35°C, with the 2023 peak reaching 35.2°C under strong subtropical ridge conditions [2]. Given the seasonal forecast for July–September 2026 indicating normal to above-normal temperatures due to the current ENSO status, a 0% probability appears inconsistent with climatological expectations unless the market is mispriced or the “YES” condition refers to an unattainable threshold [2].

Traders should monitor the Hong Kong Observatory’s Daily Extract for 21 July once finalized, as settlement depends entirely on this official data release. No external catalysts such as government announcements or weather model updates will override the Observatory’s recorded figure. The key dependency is the publication timeline of the Daily Extract, which may delay resolution beyond the settlement window if data is not finalized by 2026-07-21T12:00:00Z.

Sources: 1 · 2

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Kalshi vs Polymarket, which mirrors the Polymarket order book directly.

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 Kalshi vs Polymarket. 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.

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.

Do I need to KYC for this market?

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