Highest temperature in Hong Kong on August 2?

Platform comparison

Market context

Hong Kong’s temperature set-up has shifted little in the last 24–48 hours: the official forecast still points to a wet, unstable day, but the crowd is now pricing a fairly tight band around the high-20s rather than an outright heat spike. The Polymarket board has 27°C as the leading outcome at 34%, with 28°C close behind at 32%, which fits the Hong Kong Observatory’s forecast for a daily maximum of 28°C under persistent cloud, heavy showers and thunderstorms.[1]

That probability profile is best read against Hong Kong’s August climatology rather than against a pure heat-wave scenario. The Hong Kong Observatory’s 1991–2020 normals put 2 August’s mean maximum at 31.5°C, but August conditions are typically humid and rain-affected, which can cap daytime highs well below the seasonal ceiling.[6] August has also produced much hotter outliers in recent years, including 35.1°C in one August afternoon and a record-hot summer backdrop in 2023, so the market is really about whether cloud and rain suppress the daily peak enough to keep it in the upper 20s rather than pushing towards 29°C or higher.[2][11]

For traders, the key catalyst is the Observatory’s sequence of public forecasts, warnings and later the final “Daily Extract” entry on the climatology page, because resolution depends on the published Absolute Daily Max for the date.[13] The market will not settle until the 2 August data have been finalised by the Hong Kong Observatory, and any later revisions to the already-published figure are explicitly excluded from resolution.[1] In practice, the most important intraday driver is whether showers persist through the warmer afternoon window or thin out enough to let temperatures briefly test the upper end of the forecast range.[1]

Sources: 1 · 2 · 3 · 4 · 5

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

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.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

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.