Highest temperature in Hong Kong on August 18?

Platform comparison

Market context

On 18 August 2026, the Hong Kong Observatory will record the day's highest temperature in degrees Celsius. This market resolves to whichever temperature band contains that single daily maximum reading, with settlement contingent on official publication of the "Absolute Daily Max" figure in the Observatory's Daily Extract database.

August represents Hong Kong's peak summer season, with historical daily maxima typically ranging between 31 and 34 degrees Celsius. The 0% crowd probability suggests traders are either awaiting resolution data or treating this as a placeholder contract pending clarification on available temperature bands. Without published odds from major sportsbooks—which rarely cover weather specifics—the prediction market's current reading stands isolated from conventional betting comparisons. Historical August patterns from the Observatory show that temperatures exceeding 35 degrees occur in roughly 5–10% of years, whilst readings below 30 degrees are uncommon but not unprecedented during monsoon disruptions.

Traders monitoring this contract should track the Hong Kong Observatory's seasonal forecasts and any tropical cyclone activity in the weeks preceding mid-August 2026, as both significantly influence daily temperature ranges. The settlement window closes at midday UTC on 18 August, though actual resolution depends on when the Observatory publishes its Daily Extract data—typically within days of the observation date. Any unusual atmospheric patterns, including typhoon proximity or sustained high-pressure systems, would shift expected temperature distributions materially.

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 Best Prediction Markets. 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.

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