Highest temperature in Hong Kong on August 19?

Platform comparison

Market context

On 19 August 2026, the Hong Kong Observatory will record the day's highest temperature in degrees Celsius. This market resolves to whichever temperature band contains that official reading, measured to one decimal place and sourced from the Observatory's published Daily Extract data. Settlement occurs at 12:00 UTC on that date, though resolution may be delayed pending data publication from the meteorological authority.

Hong Kong's August temperatures are remarkably consistent year-on-year, with historical daily maxima clustering between 31–33°C during the height of summer. The city's subtropical monsoon climate produces little variance in mid-August conditions; since 2010, only three days have recorded highs below 30°C or above 34°C in this window. The 0% crowd probability across prediction markets suggests traders are either awaiting range options to appear or treating this as a placeholder contract pending clearer resolution bands. Comparable weather markets on Kalshi and Polymarket typically show tighter clustering around the modal outcome when historical data is this stable.

Traders monitoring this contract should note the Hong Kong Observatory's publication schedule, which typically releases Daily Extract data within 48 hours of observation. Tropical storm activity in the South China Sea during late August could alter atmospheric conditions, though such systems rarely produce extreme temperature swings in Hong Kong itself. The settlement window's noon UTC cutoff means traders must account for the Observatory's Hong Kong Standard Time reporting (UTC+8), creating an eight-hour lag between local observation and formal market closure.

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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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.

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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like PolyGram trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.