Highest temperature in Hong Kong on August 21?

Platform comparison

Market context

On 21 August 2026, the Hong Kong Observatory will record the day's highest temperature in degrees Celsius. A prediction market has been created to let traders forecast which temperature range will contain that maximum reading. When you buy a YES share, you're betting that the actual temperature falls within a specific bracket; a NO share means you're betting it doesn't. The market settles once the Observatory publishes its official daily extract, which records the absolute daily maximum to one decimal place.

Hong Kong's August climate is consistently hot and humid, with historical daily maxima typically ranging between 31°C and 34°C. The Observatory's records show that extreme heat above 35°C occurs occasionally but remains uncommon for mid-August, whilst readings below 30°C are rare. The current crowd-implied probability of 0% YES suggests traders are either waiting for the specific temperature brackets to be defined or reflecting genuine uncertainty about which range will prove most likely. Understanding the seasonal baseline—that August in Hong Kong rarely produces temperature extremes—provides essential context for evaluating any forecast.

The settlement depends entirely on the Observatory's official publication schedule. The Observatory typically releases daily climate data within days of observation, though the exact timing can vary. Traders should monitor the Hong Kong Observatory's website for the "Daily Extract" publication for 21 August 2026. Factors affecting the outcome include tropical cyclone activity, which can suppress temperatures through cloud cover and rainfall, and high-pressure systems that can drive readings upward. Any significant weather systems developing in late July or early August may influence expectations.

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Prediction Market UK, which mirrors the Polymarket order book directly.

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

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.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

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%.