Highest temperature in Hong Kong on August 13?

Platform comparison

Market context

The Hong Kong Observatory will record the single highest temperature on 13 August 2026, measured in degrees Celsius to one decimal place. This market resolves to whichever temperature band contains that daily maximum once the Observatory publishes its official data in the "Daily Extract" section of its climate records.

August is Hong Kong's hottest month, with daily maxima typically ranging between 31°C and 34°C. Historical records show that extreme heat days—those exceeding 35°C—occur roughly once every few years during summer, though they remain statistical outliers. The 0% implied probability suggests the crowd expects a relatively moderate day, clustering around the seasonal norm rather than an exceptional heat event. This consensus reflects August's consistency: whilst the month is reliably hot, truly extreme temperatures require specific atmospheric conditions (sustained high pressure systems, minimal cloud cover, reduced wind) that don't materialise every year.

The key variable is whether a heat dome or extended anticyclonic system settles over southern China in early August 2026. Such patterns typically develop in late July and are identifiable in medium-range forecasts by early August. The Observatory's own seasonal outlooks, published in early summer, will provide initial guidance on whether conditions favour above-average temperatures. Traders should monitor tropical cyclone activity in the western Pacific during late July and early August, as storm systems can disrupt heat accumulation. The settlement window closes at noon on 13 August, allowing only morning forecasts to inform final positioning.

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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 Who Will Win 2026. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

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.