Highest temperature in Hong Kong on July 18?

Platform comparison

Market context

Hong Kong's summer temperatures in mid-July typically peak between 32 and 35 degrees Celsius, though the Observatory has recorded extremes as high as 36.3°C during particularly intense heat waves. The settlement window closes at noon UTC on 18 July 2026, meaning the absolute daily maximum recorded by the Hong Kong Observatory for that calendar date will determine which temperature band resolves as YES. The Observatory publishes daily climate extracts with one-decimal precision, making this a straightforward factual resolution once the data becomes available—usually within days of the observation date.

Historical July records show Hong Kong experiences considerable day-to-day variance. Between 2015 and 2024, the highest temperatures on any given mid-July date ranged from 30.8°C to 35.8°C, with roughly 60% of years exceeding 33°C. The current 0% crowd probability suggests traders are either awaiting clearer seasonal forecasts or treating this as a placeholder market pending meteorological data closer to the event date. For programmatic traders, the key dependency is the Hong Kong Observatory's publication schedule; their daily climate data typically appears within 48 hours of observation, though official finalisation can take longer.

Monitoring the Observatory's seasonal outlook and tracking the Western Pacific subtropical high-pressure system in early July will provide early signals about whether conditions favour the upper or lower end of the typical range. Automated feeds from the Observatory's climate portal can be integrated into conditional order systems to trigger positions once historical patterns for that specific date emerge from comparable years.

Methodology

We track Highest temperature in Hong Kong on July 18? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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 Fees. 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.

Do I need to KYC for this market?

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