Lowest temperature in Hong Kong on August 5?

Platform comparison

Market context

Hong Kong’s low temperature on 5 August will be set by the Hong Kong Observatory’s **Absolute Daily Min** reading for that date, reported to one decimal place and only final once the Daily Extract is published. For a market wired to a precise temperature band, the practical edge is to model the overnight minimum from forecast inputs rather than the daytime high, because the settlement outcome depends on the coldest observation before the day closes in Hong Kong time. [10]

The crowd is currently pricing **0%** for YES, which is consistent with the climate baseline: Hong Kong’s August normal minimum is **26.8°C** on 5 August, and recent HKO write-ups show even rainy early-August days usually bottom out in the mid-20s rather than near 21°C or below. In 2025, for example, the Observatory’s lowest reading on 5 August was **24.0°C**, while 2020 saw **24.9°C** on the night of 5 August, which shows how unusual a materially cooler print would be. [4][1][9]

A programmatic trader would watch the Hong Kong Observatory forecast pages, the daily weather bulletin, and any thunderstorm or tropical-cyclone signal changes, then translate those into a distribution over the market’s temperature bins. The main dependency is timing: if a late-night convective burst arrives, the minimum can be pulled down after the evening forecast has already moved; if conditions stay under a warm monsoon trough, the low is more likely to cluster around the forecasted 26–27°C range already reflected in market pricing. [3][14][8]

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). 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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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 Kalshi Fees. 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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Kalshi Fees trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.