Highest temperature in Hong Kong on August 11?

Platform comparison

Market context

Hong Kong is already into a hot, unsettled day, with the Observatory issuing a forecast for “extremely hot” conditions and a maximum around 35 degrees in urban areas, a couple of degrees higher in the New Territories, alongside isolated showers later. The latest official hourly bulletin showed 28.1°C as the overnight minimum at the Observatory and 29°C at 9 a.m., which fits a day that can still climb well into the low-to-mid 30s if sunshine breaks through.[9][11]

That framing matters for reading the 0% crowd-implied probability: this is a late-summer Hong Kong setup where the daily maximum often lands in the low 30s rather than the upper 30s, but the heat ceiling remains high enough that small shifts in cloud cover and shower timing can change the top reading by a degree or two. Comparable August forecasts from weather services cluster around roughly 31–36°C today, while recent market commentary has pointed to a hot spell with maxima in the mid-30s, so the distribution is not anchored near cooler outcome bands.[1][2][3][6][8]

Traders should watch the Hong Kong Observatory’s forecast updates through the day, because the public forecast is refreshed regularly and the hourly readings can quickly reveal whether temperature is tracking towards 33–35°C or being capped by cloud and rain. The other key dependency is the settlement source itself: the market resolves only when the Observatory publishes the final Daily Extract for 11 August, and the “Absolute Daily Max” in that record will determine the winner once the data is finalised.[7][9][11]

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

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.

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%.