Highest temperature in Hong Kong on August 20?

Platform comparison

Market context

The Hong Kong Observatory will record the highest temperature in Hong Kong on 20 August 2026, measured to one decimal place in Celsius. This single daily maximum reading will determine which temperature range the market resolves to, with settlement contingent on official publication in the Observatory's Daily Extract dataset.

August temperatures in Hong Kong typically peak between 32°C and 34°C, though the city's subtropical climate produces considerable year-to-year variation. Historical records show that daily maxima in mid-August have ranged from 29.9°C to 36.0°C over recent decades. The 0% crowd-implied probability across prediction markets suggests traders are either awaiting range options to be specified or treating this as a placeholder contract pending clarification of the exact temperature bands available for resolution. This divergence from typical weather-market activity—where August Hong Kong temperatures usually attract modest trading volume—indicates potential confusion about contract mechanics rather than genuine consensus on outcome likelihood.

Traders should monitor the Hong Kong Observatory's seasonal forecasts and any tropical cyclone activity in the Western Pacific during late August 2026, as both factors materially affect daily temperature outcomes. The Observatory publishes weekly weather outlooks and issues typhoon warnings with short notice; any system approaching the region in the fortnight before settlement would suppress daytime highs significantly. The contract cannot resolve until official data appears in the Observatory's published Daily Extract, typically released within days of the observation date, creating a known lag between the event and final settlement.

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 Kalshi vs Polymarket. 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 does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

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.