Lowest temperature in Hong Kong on August 11?

Platform comparison

Market context

Hong Kong’s lowest temperature is expected to land in the upper 20s Celsius, with the Hong Kong Observatory’s own August climatology putting the 11 August daily normal minimum at 26.3°C and the long-run August absolute minimum at 26.7°C, so a sub-26°C outcome would be unusual even before considering the current weather setup.[1][11] The market’s 0% YES implication therefore sits well away from the historical baseline, while the contract’s settlement source is narrowly defined: only the Observatory’s final “Absolute Daily Min” for that date counts, to one decimal place.[1]

Comparable recent readings point to a warm overnight floor rather than an outlier cool spell. Hong Kong Observatory’s 11 August 2023 summary says the minimum reached 25.7°C, which was the lowest of that month but still a relatively mild example for August overall.[6] By contrast, the current market page on Polymarket shows the distribution concentrated on 29°C and 28°C, implying traders are still anchored to a hot-night regime rather than a cooler break.[8] That leaves little room between prediction-market pricing and the weather-based consensus embedded in the platform’s own spread.

The key catalyst is the Observatory’s hourly and daily publication cycle, because the contract cannot resolve until the final extract is posted and the market rules say later revisions to already-published readings are ignored for settlement.[5][8] Early-hour readings from the Government Information Service on 11 August already showed 28.1°C at the Observatory between midnight and 9 a.m., which is consistent with a relatively high floor before the day’s full minimum is finalised.[5] Traders will also watch the short-range forecast and any shower timing, since cloud cover and lingering tropical moisture can keep minima elevated, but the decisive input remains the Observatory’s published daily extract rather than general forecast models.[9][10]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Lowest temperature in Hong Kong on August 11? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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

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.

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.

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.