Highest temperature in Hong Kong on July 17?

Platform comparison

Market context

On 17 July 2026, the Hong Kong Observatory will record the highest air temperature in degrees Celsius across the city, and this single data point will determine the outcome of a prediction market settling into a specific temperature range. In this market, a YES share pays out if the recorded temperature falls within the chosen range, while a NO share pays out if it falls outside; currently, the crowd assigns a 0% probability to the YES outcome, implying traders believe the selected range is virtually impossible.

Historical July highs in Hong Kong typically cluster between 31°C and 34°C, with the absolute record since 1884 reaching 36.1°C in August 2017, though July peaks rarely exceed 35°C. Given that the current implied probability is 0%, the market’s selected range likely sits far above plausible extremes—perhaps 37°C or higher—making it inconsistent with decades of observed climate data from the region.

Traders should monitor the Hong Kong Observatory’s daily weather bulletins and the scheduled release of the “Daily Extract” containing the “Absolute Daily Max” figure, which finalises the settlement data. No immediate weather announcements are expected before the 12:00 UTC settlement deadline on 17 July 2026, but any sudden tropical cyclone warnings or extreme heat advisories issued by the Observatory could signal anomalous conditions. The Hong Kong Observatory’s climate archive confirms that July 2025 saw a peak of 33.8°C, reinforcing the improbability of extreme outliers without a major atmospheric driver [1].

Methodology

We track Highest temperature in Hong Kong on July 17? 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 Prediction Market 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 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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Prediction Market 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.