Lowest temperature in Hong Kong on August 6?

Platform comparison

Market context

Polymarket is pricing this Hong Kong minimum-temperature contract at **0% YES** in USDC on Polygon, so the market is effectively saying the named outcome has no live bid support for now. For a trader, the relevant number is the Hong Kong Observatory’s “Absolute Daily Min” for 6 August, because the contract resolves to the Celsius range containing that final one-decimal reading once the Daily Extract is published.

The historical backdrop is straightforward: early-August Hong Kong is typically hot and humid, with the Observatory’s 1991–2020 daily normals showing a mean minimum of 26.8°C on 6 August and 26.6°C later in the month on 26 August.[1] That makes sub-26°C outcomes relatively uncommon outside rain, cloud cover, or a stronger-than-usual easterly or monsoonal setup. Recent HKO reporting also shows how quickly the minimum can shift with weather changes: on 6 August 2025, the minimum at the Observatory reached 25.5°C by 9 a.m., illustrating that a modest cool-down is possible even in the humid season.[8]

The near-term catalysts are the Observatory’s day-of weather updates, any tropical disturbance affecting the South China coast, and the timing of the final climatological extract, which the market says it cannot resolve until the 6 August data is published.[5] HKO forecast products and hourly readings are the key dependencies for Polymarket users watching conditional tokens unwind into the eventual settlement range, while the main practical risk is that the final printed minimum can differ from early-morning readings if cooling continues later in the day.[12][8]

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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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%.