Highest temperature in Hong Kong on August 21?

Platform comparison

Market context

The Hong Kong Observatory will record the highest temperature in degrees Celsius on 21 August 2026, with settlement determined by the official daily maximum reading published in their climate data portal. The crowd currently assigns zero probability to this event resolving, suggesting either extreme confidence in a specific temperature range or insufficient liquidity across outcome brackets.

Hong Kong's August temperatures cluster tightly around historical norms. The Observatory's records show daily maxima in late August typically range between 31–34°C, with readings above 35°C occurring roughly 15–20% of the time during this period. The city's maritime subtropical climate produces consistent heat with limited volatility compared to continental locations. Extreme outliers—temperatures exceeding 36°C in August—remain uncommon but not unprecedented, having occurred in roughly one in five years over the past two decades. This historical distribution should anchor expectations around the 32–34°C bands as the modal outcomes.

Traders should monitor the El Niño/La Niña status through to August 2026, as these oscillations influence regional heat patterns across Southeast Asia. The Hong Kong Observatory publishes seasonal outlooks quarterly; the next update will arrive in spring 2026 and may shift consensus if it signals anomalously warm conditions. Typhoon activity in the Western Pacific during August could suppress temperatures through cloud cover and rainfall, though such systems typically arrive late in the month. The zero crowd probability suggests the market may lack sufficient participation to price meaningful uncertainty, creating potential value in outcome ranges currently overlooked.

Methodology

This page reviews Highest temperature in Hong Kong on August 21? 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 Who Will Win, 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 Who Will Win. 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%.