Lowest temperature in Hong Kong on July 31?

Platform comparison

Market context

Polymarket is pricing this Hong Kong Observatory minimum-temperature contract at **2% YES** on USDC collateral on Polygon, which implies the market expects the city’s lowest reading on 31 July to land inside the contract’s target range only rarely. The settlement uses conditional tokens, so the tradeable outcome is the range around the Observatory’s final **Absolute Daily Min (deg. C)** for that date, rounded to one decimal place and only resolvable once the Daily Extract is published. [16][12]

For context, Hong Kong’s July climate is normally warm and humid, with the 1991-2020 normal minimum temperature on 31 July at **26.9°C** and the older 1961-1990 normal at **26.2°C**, both far above the kind of overnight lows that would usually support a very low-range outcome. The Observatory also reported that July 2023 was exceptionally hot overall, with a monthly mean minimum of **28.0°C**, while the small-hours weather on 31 July 2023 was still showery before temperatures rebounded later in the day. [6][1][8]

The practical catalysts for holders are not broad seasonal expectations but the Observatory’s final July reporting cadence and any late data release in the climate archive, because the market cannot resolve until the relevant daily extract is posted. In a hands-on Polymarket workflow, that means checking whether the final Hong Kong Observatory entry for 31 July has appeared, then matching the published minimum against the contract’s temperature band before the window closes at **2026-07-31T12:00:00Z**. [16][2]

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 PolyGram, which mirrors the Polymarket order book directly.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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.

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.

Do I need to KYC for this market?

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