Highest temperature in Hong Kong on July 18?

Platform comparison

Market context

On 18 July 2026, the Hong Kong Observatory will record a daily maximum temperature in Celsius, and Polymarket traders are currently pricing all temperature ranges at zero probability—a technical artefact of how conditional tokens settle on Polygon when no volume has yet accumulated. The market structure divides the day's peak into discrete ranges, with USDC collateral backing whichever bracket ultimately resolves true once the Observatory publishes its official "Absolute Daily Max" figure in the Daily Extract dataset.

Hong Kong's July temperatures are remarkably consistent by global standards. Historical data shows the Observatory records daily maxima between 31°C and 35°C throughout mid-July, with the 30-year average sitting near 32.5°C. The city's subtropical maritime climate produces narrow seasonal variance; extreme outliers above 36°C or below 30°C in this window are statistically rare, occurring perhaps once per decade. This historical clustering explains why traders should expect the eventual probability distribution to concentrate heavily in the 32–34°C bands once liquidity enters the market.

The settlement window closes at 12:00 UTC on 18 July, but the Observatory typically publishes finalised daily temperature data within 24 hours of the observation period ending. Traders should monitor the Hong Kong Observatory's website directly rather than relying on third-party weather forecasts, as the resolution mechanism explicitly requires the "Absolute Daily Max" figure from the official Daily Extract. Any unusual weather systems—tropical cyclones or extended heat waves—would be visible in regional meteorological alerts weeks in advance, though such events rarely alter Hong Kong's mid-July baseline by more than 2–3 degrees Celsius.

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

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

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 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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Kalshi 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.