Lowest temperature in Hong Kong on August 10?

Platform comparison

Market context

Hong Kong’s overnight minimum on 10 August will be set by the Hong Kong Observatory’s final “Absolute Daily Min (deg. C)” reading for that date, with settlement tied to the range containing that value once the Daily Extract is published. The market cannot resolve until the Observatory finalises the data, and the contract measures temperature to one decimal place.

The crowd’s 0% YES implies the market is pricing an outcome outside the YES range, which is hard to square with August climatology in Hong Kong. The Observatory’s 1981–2010 normals put 10 August around a mean minimum of 26.3°C, while other long-run summaries place typical August lows near 27°C and cite a recorded August low of 26.7°C as the monthly floor in that sample. In practical terms, that leaves very little room for a materially colder reading unless there is an unusual synoptic setup, so the current pricing looks like a strong bet on an ordinary tropical night rather than a cool outlier.[5][11]

For traders, the key catalysts are the Observatory’s same-day and next-day updates, because the final settlement value depends on when the Daily Extract is posted and whether any late revision appears in the official record. Hong Kong’s forecast for 10 August showed a hot, humid pattern with showers and overnight lows in the low-30s °C/low-80s °F range on some commercial forecast feeds, which broadly aligns with a high-minimum-temperature regime and reinforces the market’s low implied probability of a sub-range surprise.[9][10] In crypto terms, this is a straightforward USDC-settled weather contract, so broader BTC/ETH volatility only matters indirectly through market-wide risk appetite, funding conditions, or liquidity availability rather than through the weather outcome itself.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically this overview focuses on on-chain pricing: Polymarket's live mid comes from the Polygon conditional-token order book and settles automatically in USDC. The other three venues — Kalshi, Betfair, Manifold — sit alongside as off-chain reference points so you can see how the contract translates across regulatory and settlement regimes.

Resolution & payout

Settlement is on-chain via UMA Optimistic Oracle. A proposer posts the outcome with a bond, a two-hour dispute window opens, then the smart contract lifts winning conditional tokens to 1 USDC and sends payments to holders' wallets automatically. No withdrawal fees beyond Polygon gas.

Off-chain venues (Kalshi, Betfair, Smarkets) settle in local fiat through bank-side clearing — faster than SWIFT, slower than on-chain. Manifold pays no real cash.

UK Frequently Asked Questions

What are crypto prediction markets?

Crypto prediction markets are on-chain smart contracts where you buy YES or NO shares on a future crypto event (e.g. "BTC above $100k by year-end"). The market price between 0¢ and 100¢ is the implied probability.

Why USDC and not ETH or USDT?

USDC is the Polygon standard — audited reserves (Circle, monthly attestation), deepest order book, low gas costs. ETH volatility would distort probability quotes; USDT has thinner Polygon liquidity than USDC.

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%.