Highest temperature in Hong Kong on August 3?

Platform comparison

Market context

Polymarket is currently pricing the Hong Kong 3 August temperature contract at a patchy distribution rather than a clear favourite, with the front outcomes clustered in the high-20s Celsius and the event settled in USDC on Polygon through conditional tokens. The market’s resolution will depend on the Hong Kong Observatory’s final “Absolute Daily Max (deg. C)” for 3 August 2026, so traders are effectively betting on the day’s single highest reading, not the forecast at any one hour.[2][11]

For context, Hong Kong’s early-August climatology is already hot: the Observatory’s 1991–2020 daily normals for 3 August show an average maximum of 31.4°C, with the daily mean around 28.8°C.[4] Recent summers have also produced repeated 34–35°C readings, including 35.1°C on 3 August in one hot spell and 34.3°C as the city’s hottest day of a later year so far, which shows that outcomes above the mid-30s are plausible when conditions are strongly suppressed and sunny.[1][8][15] That backdrop matters because the current crowd view implies something materially cooler than the historical normal peak, which is unusual but not impossible if cloud, rain, or onshore flow caps the maximum.[2][4]

The main catalysts are the Observatory’s hourly readings and any weather warnings or tropical-cyclone influences that shape the afternoon peak, because the “absolute daily max” is usually set late in the day if heating holds up. The Hong Kong Observatory is the only settlement source here, and its daily extract is what will matter once published; until then, the contract cannot resolve.[9][11] Traders should also watch the market’s own live repricing on Polymarket, since even small changes in the forecast can move conditional-token odds quickly on thin volume.[2]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Kalshi UK, which mirrors the Polymarket order book directly.

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 Kalshi UK. 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.