Highest temperature in Hong Kong on August 17?

Platform comparison

Market context

Hong Kong will experience peak summer heat on 17 August 2026, and this market captures the single highest temperature recorded by the Hong Kong Observatory on that date. The Observatory publishes daily maximum temperatures to one decimal place in its climate data portal, making this a straightforward settlement against a single, auditable figure. Resolution depends on the Observatory's publication schedule; historical data typically appears within days of the observation date, though traders should verify the exact release window before the settlement deadline of 12:00 UTC on 17 August.

August is Hong Kong's hottest month, with daily maxima typically ranging between 31–34°C, though extremes have occasionally exceeded 35°C. The 0% crowd probability suggests either low trading volume or genuine uncertainty about which temperature bracket will resolve. Comparing recent August records from the Observatory's historical dataset provides the baseline: the past decade shows most days clustering in the 32–33°C range, with outliers driven by typhoon proximity or sustained high-pressure systems. A trader automating this market would benefit from integrating the Observatory's daily forecast API and setting conditional orders around the 33°C and 34°C thresholds, since these represent the statistical boundary between typical and elevated outcomes.

Monitoring the meteorological outlook from mid-August onwards is essential. Tropical cyclone activity in the Western Pacific, tracked by the Hong Kong Observatory and regional agencies, can suppress temperatures significantly or, conversely, create pre-storm heat spikes. Recent precedent: August 2023 saw sustained readings above 33°C during a high-pressure ridge. Programmatic traders should flag any official heat warnings or typhoon watches issued after 10 August, as these directly influence the probability distribution across temperature bands.

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.

UK Frequently Asked Questions

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.

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.

Is Polymarket legal in the UK?

Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.

Do I pay tax on prediction market profits in the UK?

UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.

How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.