Highest temperature in Hong Kong on June 29?

Platform comparison

Market context

The real-world event is the peak daily temperature recorded by the Hong Kong Observatory on 29 June 2026, measured in degrees Celsius to one decimal place. This single data point will determine the market resolution, with the crowd currently implying a 0% probability for the "YES" outcome, suggesting the market expects the temperature to fall outside the specific range being traded.

Historical and comparable cases frame this probability sharply. June in Hong Kong consistently delivers extreme heat, with the 2026 forecast showing daily highs between 87°F and 92°F (approximately 30.6°C to 33.3°C), and the average high reaching 90°F (32.2°C)[1]. Recent records reinforce this trend: Hong Kong recorded its hottest day of 2026 on a Friday with temperatures hitting 34°C at the Observatory and peaking at 36.7°C in Sheung Shui[8]. The Hong Kong Observatory has explicitly warned of above-normal temperatures for June through August 2026, citing ENSO status and climate models[2]. A programmatically approaching trader would note that the 0% crowd probability contradicts the strong historical baseline of temperatures exceeding 34°C, as seen when the city hit 34.6°C earlier this year[6].

Traders must monitor the Hong Kong Observatory’s "Daily Extract" publication schedule, as the market cannot resolve until the "Absolute Daily Max" is finalized[2]. The primary catalyst is the official release of the daily climate data, which typically occurs after the settlement window closes. Recent news confirms the Observatory’s warning of extreme heat, with New Territories temperatures expected to hit 37°C in similar conditions[3]. A power-user evaluating tooling would set conditional orders to trigger only upon the confirmed publication of the Daily Extract, ensuring the trade aligns with the verified data rather than speculative forecasts. The dependency is strict: no resolution occurs without the finalized extract, making the timing of this publication the critical variable for execution.

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 Polymarket Review UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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.

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.