Highest temperature in Hong Kong on August 18?

Platform comparison

Market context

Hong Kong's summer heat in mid-August typically peaks between 32 and 34 degrees Celsius, though extreme conditions can push readings above 35°C. The Hong Kong Observatory records daily maximum temperatures at its headquarters in Sheung Wan, with historical data spanning decades. On 18 August 2026, this market will settle based on the Observatory's published "Absolute Daily Max" figure, measured to one decimal place. The settlement window closes at noon UTC on that date, though the Observatory typically publishes daily climate data within 24 hours of observation.

Historical August records show Hong Kong experiences considerable year-to-year variation. The all-time August maximum stands at 36.3°C, recorded in 1967, whilst cooler Augusts have seen daily highs below 30°C. The 30-year average for mid-August sits around 32.5°C. This baseline matters for calibrating probability ranges: markets currently showing 0% implied probability suggest traders expect readings outside extreme upper bounds, though the specific temperature brackets available will determine whether this reflects genuine consensus or merely sparse liquidity at tail outcomes.

For programmatic traders, the key dependency is the Observatory's publication schedule. The data source updates daily on their climate information system, making this market suitable for conditional order logic tied to automated weather feeds. Tropical cyclone activity in the Western Pacific during early-to-mid August could materially shift conditions; the 2023 season saw Typhoon Haikui influence Hong Kong temperatures in late August. Monitoring the Joint Typhoon Warning Center forecasts and the Observatory's own storm warnings provides the primary catalyst signal for reassessing temperature range probabilities ahead of settlement.

Methodology

This page reviews Highest temperature in Hong Kong on August 18? 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 Polymarket Review UK, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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 Polymarket Review UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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%.