Highest temperature in Hong Kong on August 7?

Platform comparison

Market context

Hong Kong’s highest temperature on 7 August will be set by the Hong Kong Observatory’s final **Absolute Daily Max** reading, and the market is currently trading against a **0% YES** crowd-implied probability. That looks out of line with the official forecast, which at 5:10 UTC called for **around 34°C in urban areas** and **a couple of degrees higher in the New Territories**, with temperatures in parts of the New Territories potentially reaching **36°C or above** later in the period[5].

For context, Hong Kong in August is routinely hot enough that small forecast shifts matter for a contract like this, where the settlement depends on the *single highest observation* rather than an average. The Observatory has already flagged this as part of an extreme-heat spell, and local reporting earlier in the summer noted that 2026 had already produced the year’s hottest day, underscoring that upper-30s readings are not extraordinary in this market regime[4][19]. Against that backdrop, a zero-percent market price implies either very aggressive scepticism about a new daily high or a lack of liquidity rather than a genuine view that a hot afternoon cannot print.

The main catalysts are the Observatory’s morning, midday and afternoon updates, plus whether showers or squally thunderstorms arrive early enough to cap the peak temperature. The official forecast says isolated showers and thunderstorms may develop later, while the outlook still expects high temperatures to persist over the following few days and extreme heat over the weekend[5]. The key dependency is the Observatory’s final Daily Extract, since the market cannot resolve until the 7 August data is published, so traders will be watching not just the daytime peak but also the timing of any cloud build-up or sea-breeze relief.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Kalshi vs Polymarket, which mirrors the Polymarket order book directly.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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 Kalshi vs Polymarket. 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'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 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.