Highest temperature in Hong Kong on August 14?

Platform comparison

Market context

Polymarket has this contract at **0% YES** on USDC collateral, so the market is pricing an August 14 Hong Kong Observatory maximum temperature outcome as effectively outside the current consensus. Because the contract settles via conditional tokens on Polygon, the only thing that matters is the Hong Kong Observatory’s final “Absolute Daily Max (deg. C)” for that date once the Daily Extract is published, not any private estimate or live city forecast.

For context, August in Hong Kong is usually hot enough that daily highs cluster around **31°C** in the Observatory’s climatological normals, with a mean maximum of **31.4°C** and a mean temperature of **28.8°C** on the HKO climatology page.[14] Recent weather summaries also show that Hong Kong can still post very warm August days late in the month, and 2025 was described by the Observatory as an “exceptionally hot August”, with a mean daily maximum of **31.7°C**.[11] In practical market terms, a 0% reading implies traders are not currently assigning meaningful weight to an outcome that lands in any settlement band above the listed floor, even though the underlying climate regime makes extreme heat a normal summer feature rather than a tail event.[2][14]

The main catalysts are procedural rather than dramatic: the contract cannot resolve until the Hong Kong Observatory publishes the finalized daily extract for 14 August, and traders should watch for that release rather than intraday station readings.[3][14] Any late update to the Observatory’s data page, or a correction to the daily maximum after the initial posting, would matter more than headline forecasts. In weather markets, the key dependency is the official source’s archived figure, because that is what will determine the winning conditional token set on Polygon and the USDC payout at settlement.[3][14]

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

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

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is PolyGram. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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%.