Lowest temperature in Hong Kong on August 8?

Platform comparison

Market context

Polymarket has this contract at **0% YES** right now, so the market is effectively pricing in no expectation that Hong Kong Observatory’s lowest temperature for 8 August 2026 will land in a winning range. On Polymarket, traders are not buying the weather itself but conditional tokens settled in **USDC** on **Polygon**, with the outcome determined by the Hong Kong Observatory’s published “Absolute Daily Min (deg. C)” in its daily extract once finalised.[11][6]

The historical frame is that Hong Kong’s August nights are usually warm, with the Observatory’s 1991–2020 normals showing an average **minimum of 26.9°C** on 8 August, alongside mean temperatures close to 29°C.[1] Broader August climatology also points to sticky, humid conditions, with typical lows around the mid- to upper-20s Celsius rather than anything cool enough to make a low-temperature market highly dispersed.[2][10] For a trader, that means the relevant question is less “will it be hot?” and more whether an unusually wet, cloudy, or windy overnight pattern could nudge the minimum below the seasonal norm.

The main catalysts are the Observatory’s forecast updates, the hourly readings through the night, and the eventual daily extract that locks in the official minimum. At 3 a.m. local time, the Observatory was already reporting **29°C** at the observatory and **27–30°C** across several stations, which is consistent with a mild-to-warm overnight floor rather than a sharp dip.[14] Recent weather reporting also points to mainly cloudy August conditions with highs still in the mid-30s forecast for the day, so traders watching the on-chain price will be focused on whether late-night showers or a stronger breeze materially alter the minimum before settlement.[19]

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%.