Highest temperature in Hong Kong on August 4?

Platform comparison

Market context

Hong Kong’s maximum temperature on 4 August will be set by the Hong Kong Observatory’s final “Absolute Daily Max (deg. C)” for that date, with the market resolving to the temperature band that contains the published one-decimal reading. At the time of writing, the crowd is assigning **0%** to **YES** on the contract as framed here, while Polymarket’s live book on the same event shows **30°C** as the leading outcome at **40%**, ahead of **29°C** at **34%** and **31°C** at **13%**.[2] That gap suggests the market-specific framing is being priced much more cautiously than the broader outcome distribution, or that traders are still waiting for the observable daytime temperature peak to develop before committing capital.[2]

Recent Hong Kong summer readings provide a useful benchmark: the city has already posted extreme heat this year, including a hottest-day print of **34.6°C** reported by the South China Morning Post, with other outlets noting highs above **32°C** in separate hot spells.[9][11] Against that backdrop, a result in the **29°C–31°C** band would be consistent with the current prediction-market front-runner, but a materially hotter reading remains plausible in late-summer conditions when humidity, local convection and urban heat can all push the day’s maximum above forecast norms.[2][9] Seasonal guides for August generally put Hong Kong in the low-30s Celsius, reinforcing why the distribution clusters around 29–31°C rather than colder bands.[7][10]

Traders should watch the Hong Kong Observatory’s daytime updates, including regional weather readings and any thunderstorm or typhoon-related notices, because cloud cover and rain can cap the afternoon maximum quickly.[6][18] The contract cannot settle until the Observatory publishes the final daily extract, so the key dependency is the timing of that official post-processing rather than intra-day forecasts alone.[13] Short-term forecast products also point to unsettled August weather, including a 4 August outlook that one source summarises as rain with a roughly **30°C** high, which aligns more closely with the current Polymarket lead than with the market’s 0% crowd-implied YES reading.[14][2]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in Hong Kong on August 4? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Best Prediction Markets UK, which mirrors the Polymarket order book at 0% fees.

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 Best Prediction Markets UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.