Highest temperature in Hong Kong on August 15?

Platform comparison

Market context

Hong Kong’s highest temperature on 15 August will be the day’s peak reading from the Hong Kong Observatory, reported in Celsius to one decimal place and only settled after the Observatory publishes its final daily extract. A YES share pays if the final figure falls within the market’s specified range; a NO share pays if it does not. With the crowd at 0% YES, the market is implying that traders see little chance of a high enough reading landing in the targeted band.

The setup should be read against Hong Kong’s mid-August climate, when the Observatory’s 1991–2020 normals put the mean maximum for 15 August at 30.8°C and the mean temperature at 28.4°C. That makes the relevant range very sensitive to the exact bucket chosen by the contract, because a small shift of a few tenths can move the final value between adjacent temperature bands. Recent forecasts also point to a hot, unsettled day: the Observatory’s 14 August bulletin said temperatures would range between 27 and 31 degrees, with showers and thunderstorms still affecting the area at first.

For traders, the key catalysts are the Observatory’s day-of updates, the timing of the 9-day forecast, and the final publication of the Daily Extract on or after the settlement window. The market cannot resolve until the 15 August data is finalised, so any late changes from rain, cloud cover, or lingering thunderstorms matter more than the earlier forecast headline. The settlement source is the Hong Kong Observatory’s climatological archive, not a private weather app, so only the official extracted maximum will count.

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Methodology

This page reviews Highest temperature in Hong Kong on August 15? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Prediction Market UK, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

UK Frequently Asked Questions

Is this market available outside the US?

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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%.