Highest temperature in Hong Kong on July 17?

Platform comparison

Market context

Hong Kong faces its peak summer heat today as the city awaits the official highest temperature recorded on 17 July 2026, a figure that will determine the outcome of a Polymarket contract priced at 0% for the “YES” side. Traders on Polygon are locking USDC into conditional tokens, betting on whether the Hong Kong Observatory will publish a daily maximum within a specific Celsius range once the “Daily Extract” is finalized. The market remains dormant until the data is officially released, reflecting the on-chain mechanic that prevents settlement before the resolution source confirms the absolute daily max.

Historically, mid-July in Hong Kong routinely sees temperatures between 31°C and 34°C, with the 2023 record for 17 July hitting 33.8°C, suggesting the current 0% probability likely targets a narrow, high-end range that has not yet been breached in recent years [1]. Comparable cases from the last decade show that while extreme heatwaves can push readings above 34°C, the median daily maximum for this date clusters tightly, making outlier ranges statistically improbable until confirmed by the Observatory’s final dataset.

Traders should monitor the Hong Kong Observatory’s “Daily Extract” release schedule, which typically publishes finalized climate data within 24–48 hours after the observation date, as this is the sole catalyst for market resolution [1]. No external announcements or weather forecasts will override the official recorded value; the market’s fate depends entirely on the Observatory’s published “Absolute Daily Max (deg. C)” in the CSV dataset. Until that figure appears, the on-chain position remains frozen, with liquidity tied to the timing of the data publication rather than speculative weather models.

Sources: 1

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

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 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 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.