Lowest temperature in Hong Kong on August 11?

Platform comparison

Market context

Hong Kong’s overnight low on 11 August will be set by the Hong Kong Observatory’s official station reading, measured in one decimal place and resolved from the Daily Extract once published. The current crowd-implied probability on the contract is 0% for YES, which is materially lower than the direction implied by the live weather market and local forecast sources: Polymarket’s own visible pricing has 29°C as the clear lead outcome at 72%, with 28°C at 17%, while short-range forecasts from Timeanddate and AccuWeather point to a very warm night with lows around 28–29°C rather than anything near the seasonal norm.[8][11][13]

Historical context supports treating this as a high-low-end temperature range market rather than a binary cold-snap bet. Hong Kong’s August normal minimum is about 26.7°C, and weather references for the city put typical August night-time lows near 27°C, but the official observed minimum can vary by a degree or two from the forecast, especially with cloud cover, showers and humidity limiting radiative cooling.[2][12] The highest-value comparable signal is that the market is already pricing a very warm floor: if the eventual HKO minimum lands at 28.0°C or 28.1°C, the contract resolves very differently than 29.0°C, so the key comparison is not just “hot versus cool” but which exact temperature band contains the official minimum.[8][10]

Traders should watch the Hong Kong Observatory’s hourly readings through the morning, then the “Press Weather” update and the final Daily Extract publication, because the market cannot settle until the station data is finalised.[7][10] The main dependency is whether overnight showers or lingering cloud trim the minimum below current expectations; absent that, the live forecast ensemble and existing exchange pricing are both aligned around a minimum in the upper 20s, leaving the 0% YES crowd view out of step with both the weather model signal and the prediction-market consensus.[8][11][18]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Lowest temperature in Hong Kong on August 11? 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.

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.