Highest temperature in Hong Kong on July 3?

Platform comparison

Market context

On 3 July 2026, the Hong Kong Observatory will record the highest daily temperature in degrees Celsius, a single real-world figure that determines whether a YES share pays out. A YES share wins only if the recorded maximum falls within the specific temperature range offered in the market; a NO share wins if it falls outside that range. In this case, the crowd-implied probability for the current range is 0%, suggesting traders believe the actual maximum will not land there.

Historical and seasonal data frame this near-zero probability. The Hong Kong Observatory’s seasonal forecast for July–September 2026 expects normal to above-normal temperatures, with daily highs in July typically ranging from 86°F to 96°F (30°C to 35.5°C) [2][3]. Recent daily extracts show a maximum of 31°C on 3 July 2026 so far, but the final official value will be higher once the “Daily Extract” is finalized [4]. Given the trend toward above-normal heat, the current range likely sits too low to capture the expected peak.

Traders should monitor the Hong Kong Observatory’s final “Daily Extract” publication, which releases the official “Absolute Daily Max” only after data is finalized [2]. No weather announcement will override this source; the market resolves strictly on the published figure. Watch for any updates on ENSO status or climate model revisions that could shift temperature expectations, as these are cited in the Observatory’s current seasonal guidance [2]. The settlement window ends 2026-07-03T12:00:00Z, after which the official value becomes binding.

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

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 Prediction Market UK. 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.

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.