Highest temperature in Hong Kong on August 9?

Platform comparison

Market context

Hong Kong’s outcome here will be set by the Hong Kong Observatory’s final **Absolute Daily Max** for 9 August, measured to one decimal place, not by any app’s headline high or a forecast page. For a programmatic workflow, the cleanest approach is to poll the Observatory’s daily extract once it is published, then map the final Celsius value into the market’s stated range; until that file appears, any live price is really a proxy for expected weather rather than a settled reading.[2][4][17]

The current **0% YES** looks like a data-availability artefact rather than a strong statement about the temperature itself, because the market cannot resolve until the Observatory publishes the relevant daily extract. That matters for comparables: Hong Kong’s August climatology is hot, with a 1991–2020 normal daily maximum of about **31.6°C** on 9 August, and recent summers have produced several days in the mid-30s at the Observatory and higher values in outlying districts.[7][5][6] In other words, traders should treat any empty or stale probability as a tooling problem to monitor, not as a forecast of a cool day.[7][17]

The key catalyst is the Observatory’s publication schedule: the midday-to-evening evolution of temperatures can still shift the final max, but the market only settles when the verified daily extract is posted. A useful bot setup is to watch the Observatory text feeds and regional readings, then compare them with the forecast and hourly updates during the day; the HKO’s own hourly and regional pages give the best live signal, while media reports can help confirm whether the city is in an exceptionally hot spell.[2][10][5]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Hong Kong on August 9? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

Resolution & payout

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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.

UK Frequently Asked Questions

Where can I trade this market with the lowest fees?

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How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.