Highest temperature in Hong Kong on August 2?

Platform comparison

Market context

Hong Kong’s highest temperature on 2 August will be set by the Hong Kong Observatory’s “Absolute Daily Max” for that date, and the market will not settle until the finalized daily extract is published. The current crowd view is sharply skewed towards cooler outcomes, with the market showing 27°C and 28°C as the leading bands rather than anything in the low 30s, while the broader forecast context points to unsettled weather rather than extreme heat.[3][1]

Historically, August in Hong Kong is warm enough that a high in the high-20s is ordinary, but the tail risk sits with brief hot spells when cloud cover and rainfall fail to materialise. The Observatory’s official August forecast points to a 24–28°C range with persistent cloud, heavy showers and thunderstorms, while third-party forecast pages still cluster daily highs around the high 20s to low 30s, which supports why the market is pricing the outcome around 27–28°C rather than the upper brackets.[3][1][9] That leaves the 0% implied probability on a 31°C-or-higher resolution as a meaningful divergence from the published weather outlook, though not a contradiction: prediction markets often discount the far tail when the forecast calls for rain.

Traders should watch the Observatory’s short-range updates, thunderstorm and typhoon signals, and any intraday shift in rainfall timing, because these can cap the day’s maximum temperature even if morning conditions start warm.[10][3] The main dependency is the official reading at the Hong Kong Observatory station and the later daily extract, not live market chatter, so any late-day clearing or delayed showers would matter more than broader seasonal averages.[2][3]

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

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'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 Best Prediction Markets trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.