Highest temperature in Hong Kong on August 10?

Platform comparison

Market context

Hong Kong’s hottest reading on 10 August is the event in play, and the market is pricing a **0% YES** chance that the day’s maximum lands in the selected band. That makes **NO the clear favourite**, with the consensus effectively saying the temperature outcome is already assumed to be outside the YES range unless the final Observatory figure comes in as an outlier.

The useful frame is that Hong Kong can post very sharp August heat, but the distribution is still anchored by the Observatory’s own climate normals: the 1991–2020 daily normal maximum for 10 August is **31.4°C**, with a normal mean around **28.9°C**. Against that baseline, the recent extreme is instructive rather than decisive: on 10 August 2025 the Observatory’s maximum reached **34.4°C**, while 9 August 2026 produced **36.9°C**, the city’s hottest reading on record, showing that late-summer spikes can outrun the climatology when regional heat is reinforced by broader synoptic conditions. That leaves the favourite with a strong statistical edge, but the contrarian angle is that the market’s 0% implies almost no allowance for another exceptional spike, so any value would sit only if the settlement band is set high enough to absorb a record-level print.

Traders should watch the Hong Kong Observatory’s hourly readings and the final Daily Extract, because settlement depends on the published **“Absolute Daily Max (deg. C)”** rather than forecast temperatures. The opening day setup already looked hot, with extended-forecast sites showing highs in the mid-30s Celsius and government weather reporting active hourly observations, so the key catalyst is whether the afternoon peak is capped by cloud, showers or sea breeze, or whether the heat persists into the observation window. The consensus remains firmly with **NO**, but if the market band is narrow and centred below the recent record, the only real value would be in fading the assumption that another near-record day is impossible.

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

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 Who Will Win 2026. 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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Who Will Win 2026 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.