Highest temperature in Hong Kong on August 10?

Platform comparison

Market context

Hong Kong’s 10 August high is a **weather handicap** on a very warm late-summer day, with the market currently pricing **0% YES** despite the city’s August climatology clustering around the low 30s Celsius. The favourite is still a sub-34°C finish if showers or cloud cap the afternoon, but the underdog case is straightforward: one hot, dry spell is enough to push the Observatory’s **Absolute Daily Max** into the upper 30s and force a range break. Hong Kong’s August normal mean maximum is about **31.1°C** for 10 August, while recent August outcomes have often landed in the low-to-mid 30s rather than the high 20s.[3][9][11]

Comparable recent readings show the tail risk is real. The Observatory said 10 August 2025 reached **34.4°C**, the month’s peak, and its 2024 August summary describes the period as exceptionally hot, with a mean daily maximum of **32.3°C** for the month.[15][9] Market consensus therefore appears to sit around a low-30s bucket, with value more likely on the contrarian higher-temperature bands if the day turns sunnier than expected. The 0% crowd price suggests the market is treating a very hot outcome as near-impossible, which looks aggressive given how often Hong Kong prints 32°C-plus in August.[9][11]

Traders should watch the Hong Kong Observatory’s **daily extract** for the final “Absolute Daily Max” once it is published, because this market cannot settle until that data is finalised.[1] For the live setup, the key catalyst is whether the day follows the hot 10 August template seen in prior years or shifts into a wetter, cloudier regime; recent commercial forecasts were already flagging very warm conditions around **97°F/36°C** with showers or thunderstorms in the mix.[13][16][17] That makes the favourite sensitive to convective weather timing, while the value spot sits in any band that assumes the heat is blunted before the day’s maximum is set.

Sources: 1 · 2 · 3 · 4 · 5

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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

UK Frequently Asked Questions

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 Who Will Win. 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.

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%.