Highest temperature in Hong Kong on July 9?

Platform comparison

Market context

On 9 July 2026, Hong Kong will face its peak summer heat as the Hong Kong Observatory records the absolute daily maximum temperature in degrees Celsius, a figure that will determine the outcome of a prediction market currently implying zero probability for any temperature above the lowest range. This real-world event hinges on a single decimal-point measurement from the Observatory’s official "Daily Extract", which finalises only after data is published and verified.

Historical July temperatures in Hong Kong consistently exceed 30°C, with average highs around 32°C and frequent peaks reaching 34–35°C, making the current 0% implied probability for higher ranges starkly divergent from both climate norms and seasonal forecasts that predict normal to above-normal temperatures for July–September 2026[1]. AccuWeather’s monthly forecast for July 2026 cites daily highs between 29°C and 35°C (85°F–95°F), reinforcing that a result in the lowest range would be an extreme outlier[2].

Traders should monitor the Observatory’s 9-day forecast updates and the release schedule for the "Daily Extract" for 9 July, as delays in data finalisation could postpone market resolution[8]. Recent regional forecasts indicate a temporary cooling trend this weekend, with temperatures dropping to 13°C, but this is unlikely to persist into mid-July when summer heat typically intensifies[3]. No official announcements have yet confirmed anomalies, so the catalyst remains the Observatory’s routine data publication cycle.

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

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

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.

Do I need to KYC for this market?

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

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.