Highest temperature in Hong Kong on August 4?

Platform comparison

Market context

Hong Kong’s peak temperature on 4 August will be set by the Hong Kong Observatory’s final **Absolute Daily Max** reading, not by a private forecast model, and the market will not resolve until that daily extract is published in Celsius to one decimal place. For a programmatic trader, the cleanest workflow is to watch the Observatory’s daily readings feed, map the reported maximum to the market’s outcome buckets, and update positions only when the official observation is effectively locked in.

The current 0% YES crowd-implied probability is hard to read as a directional signal because the market’s pay-off is tied to a single realised value, yet late-summer Hong Kong maxima often cluster tightly around the high-20s to low-30s Celsius unless a heat alert or a stronger offshore flow pushes the day hotter. The live market page is already pricing the most likely outcomes around 29°C and 30°C, with 30°C at 40% and 29°C at 34%, which is consistent with a narrow distribution rather than a broad swing state[2]. That makes this a fairly mechanical market for copy-trading or conditional orders: traders usually key off the latest observed forecast band, then wait for any deviation in the morning updates that can shift the modal bucket by one degree[2][7].

The main catalysts are the Observatory’s short-term forecast updates, any issued heat warnings, and whether showers or cloud cover persist long enough to suppress the afternoon maximum. Hong Kong’s official weather pages and regional readings update through the day, and the Observatory’s public readings already showed temperatures in the high 20s in parts of the city on 4 August[4][7]. Recent reporting also shows the city has already experienced multiple 2026 days above 34°C, underlining that small changes in cloud, wind and rain can move the final settlement bucket by a full degree[5][9].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Hong Kong on August 4? 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

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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Kalshi Fees trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

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.