Highest temperature in Hong Kong on July 3?

Platform comparison

Market context

The real-world event driving this market is the absolute daily maximum temperature recorded by the Hong Kong Observatory on 3 July 2026, measured in degrees Celsius to one decimal place. This single data point will determine which temperature range the market resolves to, with the settlement window closing at 12:00 UTC on 3 July 2026. The current crowd-implied probability of 0% for the "YES" outcome suggests traders believe the temperature will fall outside the specific range being offered, likely due to historical patterns or current forecasts.

Historical data frames how to interpret this near-zero probability. July in Hong Kong is consistently hot, with average highs around 31.7°C (89°F) and frequent peaks exceeding 33°C (91°F), as noted in the Observatory’s 30-year climate records[6]. Recent years show July 2023 was the city’s hottest month on record, with the highest number of hot days and nights since 1884[8]. The 2026 forecast for July indicates daily highs ranging from 30°C to 35.5°C (86°F to 96°F), with an average high of 31.7°C[1]. A power-user would programmatically scrape the Observatory’s "Daily Extract" for the "Absolute Daily Max" value once finalized, comparing it against the market’s range thresholds to execute conditional orders.

Traders must monitor the Observatory’s data publication schedule, as the market cannot resolve until the "Daily Extract" is finalized. The dependency is strict: no official data means no settlement. A recent SCMP report confirmed July 2023 as the hottest month ever recorded, highlighting the volatility and potential for extreme values in summer months[8]. For a 2026 event, the key catalyst is the release of the official climatological data on 3 July, which will confirm whether the temperature exceeds the market’s upper bound. Programmatic traders should set up automated alerts for the Observatory’s climatological information page to trigger trades immediately upon data release[6].

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.

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.

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