Highest temperature in Hong Kong on August 20?

Platform comparison

Market context

On 20 August 2026, the Hong Kong Observatory will record a daily maximum temperature in Celsius, and this market settles to whichever temperature band contains that reading. The crowd is currently pricing all outcome ranges at 0% probability on Polygon, meaning no USDC has flowed into any conditional token yet—an unusual state that typically reflects either extreme uncertainty or insufficient liquidity to establish meaningful odds. Settlement depends entirely on the Observatory's published "Absolute Daily Max" figure, released through their Daily Extract once the date passes and data finalisation is complete.

Hong Kong's August temperatures cluster tightly around historical norms. The Observatory's records show August daily maxima typically range between 31–34°C, with extreme heat occasionally pushing toward 36°C during particularly intense heatwaves. The 1997 heatwave saw readings exceed 35°C on multiple days; more recently, August 2023 recorded several days above 33°C. This historical band—31–35°C—has captured the vast majority of August outcomes over the past three decades, providing a baseline against which outlier scenarios (sub-31°C or above 36°C) should be evaluated.

Traders should monitor tropical cyclone activity and upper-atmosphere pressure patterns in early August 2026, as these drive Hong Kong's late-summer heat. The Hong Kong Observatory issues seasonal outlooks in July; any forecast emphasising above-normal temperatures or blocking high-pressure systems would signal elevated probability for readings above 34°C. Conversely, a passing typhoon or monsoon trough could suppress maxima below the historical median. Real-time tracking of the Western Pacific typhoon season and regional weather models in mid-August will sharpen probability estimates as the settlement date approaches.

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

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.

FAQ

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.

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

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.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.