Lowest temperature in Hong Kong on August 5?

Platform comparison

Market context

Hong Kong’s observatory minimum on 5 August will be judged against the Hong Kong Observatory’s published “Absolute Daily Min (deg. C)” for that date, so the contract settles on the exact daily low rather than a generic city forecast.[10] The crowd is already pricing a **27°C** outcome at about **96%**, with **26°C** a distant second at around **5%**, which leaves very little implied chance on the lower buckets and makes the current line look far firmer than a balanced weather book.[1]

That pricing is broadly consistent with Hong Kong’s late-summer climatology. The Observatory’s 1991–2020 daily normals show a 5 August minimum of **26.2°C**, while secondary weather guides commonly place early-August lows around **27°C**, so a 27°C print sits close to the historical centre of gravity rather than at an extreme.[3][5] Comparable recent years also show that sharper rain events can drag the minimum lower: the Observatory recorded **24.9°C** on 5 August 2020 and **24.0°C** on 5 August 2025 during wet conditions.[8][2] That history helps explain why traders have some residual tail risk in 26°C, but not enough to move the market away from 27°C as the base case.[1][2][8]

For catalysts, the key variable is not a mid-market headline so much as the final Observatory extract: the contract cannot resolve until the daily climate data is published, and the source page explicitly points traders to the climatological database for final confirmation.[10] In practical terms, late showers, thunderstorm coverage, and any tropical-weather disruption around the overnight and early-morning window are the only plausible mechanisms for a lower-than-expected minimum, because they can reduce nocturnal cooling and keep the surface layer more humid.[17] Against that, the crowd’s 96% lead on 27°C suggests there is little sportsbook-style dissent to compare with the prediction market price; if another platform were quoting this event, any meaningful gap would likely come from how aggressively it weights rain risk rather than from the calendar itself.[1]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Lowest temperature in Hong Kong on August 5? 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

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?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Best Prediction Markets. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

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.

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 Best Prediction Markets trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.