Lowest temperature in Hong Kong on July 31?

Platform comparison

Market context

Hong Kong’s observed minimum on 31 July will be measured by the Hong Kong Observatory and only settled once the final daily extract is published, so the key question is whether the day lands in the typical high-20s Celsius band or delivers a cooler outlier. The market’s 3% YES implies traders are assigning only a small chance that the lowest temperature falls into the relevant range for a notably cool reading, which is consistent with Hong Kong’s midsummer climate, where July lows are usually around 27–28°C and the monthly record minimum is 27.7°C in the Observatory’s July rankings.[2][6]

Comparable cases suggest that very low July minima in Hong Kong are possible, but generally tied to heavy rain or unusual synoptic set-ups rather than routine conditions. For example, on 31 July 2019 the Observatory reported a minimum of 24.5°C during intense rain, well below the usual July floor.[4] That helps explain why the crowd is pricing this contract as a long-shot compared with the climate baseline, even though the market still leaves room for a weather-driven dip below the norm; public weather summaries for Hong Kong point to sustained heat, humidity and only modest day-to-day variation in late July.[1][3][6]

The main catalysts are the Observatory’s hourly readings through the settlement window and the eventual publication of the daily extract, which is the only resolution source for the contract.[7][15] The most relevant dependency is whether late-morning or afternoon convection, showers or an imported cooler air mass push the day’s absolute minimum down before the window closes. Cross-platform pricing has typically been narrower than the sportsbook-style long-shot framing implied by 3%, so the practical focus is less on average July weather than on whether real-time observations justify a sharp deviation from the standard 27–28°C outcome.[2][7]

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 Best Prediction Markets UK, 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 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.

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 Best Prediction Markets UK 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.