Highest temperature in Hong Kong on June 23?

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Market context

The real-world event is the Hong Kong Observatory’s measurement of the absolute daily maximum temperature in degrees Celsius on 23 June 2026, a single data point that will settle a prediction market into a specific temperature range. This is not a forecast but a recorded fact, finalized only once the Observatory publishes its Daily Extract for that date.

Historically, June in Hong Kong has seen peak temperatures regularly exceed 33°C, with the highest monthly mean maximum recorded at 32.4°C in June 2016[3]. Recent early-June days in 2026 already hit 33–34°C on clear skies, and 2025 saw 35.6°C on 10 June, matching the 1963 record[5][6]. A current 0% probability for any outcome is therefore inconsistent with this track record, as the frontrunner in the live market is 33°C at 56–62%[1], suggesting the 0% figure may be a data error or misalignment.

Traders should monitor the Observatory’s Daily Extract release schedule, which finalizes data only after the day ends, and watch for any official heat warnings or extreme heat announcements that precede the measurement[9]. Recent SCMP reports confirm the Observatory has issued extreme heat warnings ahead of record-breaking days, such as the 36.1°C reading that broke the 1963 record[2][9]. Programmatically, a bot would fetch the Daily Extract URL, parse the “Absolute Daily Max (deg. C)” field, and map it to the correct temperature range once the extract is published, avoiding trades before finalisation.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). The odds column is filled only where we have clean data — that avoids the made-up numbers that get a network demoted when search engines cross-check against the source venue.

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?

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 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.