Highest temperature in Hong Kong on June 25?

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Market context

The real-world event is the peak daytime heat Hong Kong will experience on 25 June 2026, measured as the absolute daily maximum temperature in degrees Celsius at the Hong Kong Observatory. A power-user approaching this programmatically would treat the 0% YES crowd-implied probability as a signal to verify historical June extremes against current forecast bands, rather than assuming the market is settled. The market resolves only once the HKO publishes the finalized “Daily Extract” for that date, creating a clear dependency on official data release timing.

Historically, June in Hong Kong has frequently seen highs exceeding 34°C, with 10 June 2025 reaching 35.6°C—the record maximum for the month[1]. The monthly mean maximum for June ranks 32.4°C in 2016 as the highest on record, while 2015 and 1938 also exceeded 31°C[5]. These cases frame the current 0% probability as potentially premature, given that recent years show consistent heat spikes well above 30°C. A trader reading this should note that even a single day of extreme heat can push the daily max into the 34–35°C range, making the NO bucket less certain than the crowd suggests.

The key catalysts to watch are the Hong Kong Observatory’s weather warnings for extreme heat and the onset of the nine-day rain system forecast to begin this weekend, which could suppress temperatures to 26–30°C[3]. Traders must monitor the HKO’s daily updates for the “Absolute Daily Max” figure and the timing of the “Daily Extract” publication, as settlement hinges on this data release. Recent reports confirm HKO warned of extreme heat on 5 June 2026, with temperatures hitting 34.6°C, before the rain system arrived[9]. The dependency on official data means the market cannot resolve until the extract is finalized, so conditional orders should be set to trigger only after publication.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in Hong Kong on June 25? across five venues. We show live odds for Polymarket-based markets (sourced from the Polygon order book); for other venues we list platform attributes, since the comparable contracts are not exposed via a public API on every venue. Every CTA points at Polymarket App UK — the application we operate, where you trade directly against the Polymarket order book at 0% fees.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Where can I trade this market with the lowest fees?

On Polymarket App UK, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Polymarket App UK is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

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 it cost to trade on Polymarket App UK?

Zero. Polymarket App UK routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

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.