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 degrees Celsius. This single daily maximum will determine which temperature band resolves as correct, with settlement dependent on official data publication from the Observatory's Daily Extract records.

August temperatures in Hong Kong typically range between 28°C and 35°C, though extremes have occasionally exceeded 36°C during particularly intense heat events. Historical data from the Observatory shows that daily maxima in mid-August average around 32–33°C, with variability driven by monsoon patterns and tropical systems. The 0% crowd probability across platforms suggests traders are either awaiting clearer atmospheric forecasting or treating this as a placeholder market pending resolution criteria clarification. No comparable divergence exists between Polymarket and Kalshi lines, as both reflect minimal trading activity at this stage.

Traders should monitor the Hong Kong Observatory's seasonal forecasts and any tropical cyclone or heat-wave advisories issued in late July 2026, as these will be the primary catalysts affecting August 20 conditions. The settlement window closes at 12:00 UTC on the resolution date itself, meaning traders cannot adjust positions after local Hong Kong midnight. The Observatory publishes Daily Extract data with a lag of several days, so actual resolution may occur in late August or early September 2026. Current atmospheric models and monsoon forecasts from the China Meteorological Administration, typically released in early August, will provide the most actionable forward guidance for positioning.

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.

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.