Highest temperature in Hong Kong on July 20?

Platform comparison

Market context

The Hong Kong Observatory has not yet published the absolute daily maximum temperature for 20 July 2026, leaving the “Highest temperature in Hong Kong on July 20?” market at 0% YES for any specific range. On Polymarket, this USDC-denominated contract on Polygon trades as a set of conditional tokens that only resolve once the official “Daily Extract” data is finalized, meaning no price movement can occur until the authority releases the figure to one decimal place in Celsius.

Historically, Hong Kong’s late-July highs cluster between 31°C and 34°C, with the all‑record daily maximum of 36.1°C set in August 2017 and a recent July 2024 peak of 33.8°C; the current 0% implied probability suggests the market expects the 2026 reading to fall outside the narrow range currently offered, or that liquidity is too thin to price a specific band before data publication. Traders should note that in past years, the Observatory’s daily extract for a given date typically appears within 24–48 hours after the day ends, creating a predictable settlement lag.

The primary catalyst is the official release of the “Daily Extract” from the Hong Kong Observatory, which will list the “Absolute Daily Max (deg. C)” for 20 July; until this CSV or JSON feed updates on the data portal, the contract remains unresolved and untradeable in terms of outcome. No weather announcements or forecast schedules override this dependency, as the market rules explicitly tie resolution to the finalized observational record rather than model projections, ensuring the on-chain outcome mirrors the ground-truth measurement.

Sources: 1

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 Kalshi UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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 does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

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.

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.