Highest temperature in Hong Kong on August 17?

Platform comparison

Market context

Hong Kong's daily maximum temperature on 17 August 2026 will be recorded by the Hong Kong Observatory and published in their Daily Extract dataset. The settlement window closes at midday UTC on that date, though the actual temperature reading will not be finalised until the Observatory publishes its official daily climate summary, typically within 24–48 hours of the observation period ending. This creates a hard dependency: the market cannot resolve until that data appears on the Observatory's Climate Information Services portal.

August is Hong Kong's peak summer season, with historical daily maxima typically ranging between 32–34°C, though extremes have reached 36–37°C during heat waves. The 0% crowd probability suggests traders are either waiting for seasonal forecasts or treating this as a calibration exercise. Reviewing the Observatory's historical daily extracts reveals that August temperatures cluster predictably; a trader building a conditional order or bot to monitor this market would benefit from pulling historical August data from prior years to establish baseline distributions and flag anomalies.

The key catalyst is the meteorological forecast window opening in late July 2026. Tropical cyclone activity, monsoon patterns, and upper-air pressure systems will determine whether August 17 falls within a typical range or an outlier event. A trader automating position management would want to integrate real-time weather model outputs—particularly the GFS and ECMWF ensemble forecasts—into their decision logic roughly two weeks before settlement, when predictability becomes meaningful. The Observatory publishes weekly forecasts; tracking those updates programmatically offers an edge over manual monitoring.

Methodology

We track Highest temperature in Hong Kong on August 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

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 Kalshi Fees 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.