Lowest temperature in Hong Kong on July 31?

Platform comparison

Market context

Polymarket is pricing this Hong Kong low-temperature contract at **3% YES**, which means the market is assigning a very small chance that the Hong Kong Observatory’s 31 July minimum will land in the specified temperature range. Because settlement uses the Observatory’s final **Absolute Daily Min (deg. C)** from the Daily Extract, the trade is really on a verified official reading, not on an implied or modelled forecast, and the contract sits on Polygon with USDC collateral and conditional tokens rather than a simple binary bet.

That low price is broadly consistent with Hong Kong’s late-July climate: published climatology for the city points to daily lows around **26°C to 27°C**, with monthly averages near **29°C highs** and **26°C to 27°C lows** in July, while broader forecast pages for late July 2026 cluster overnight minima in the high 20s Celsius. July 31 is also typically near the warm end of the seasonal range, so a payout on a lower temperature band would usually need an unusually cool overnight reading or a strong rain-cooled dip. Past HKO July reports show the month can still produce very hot final days even when showers and thunderstorms are around, which is why the market’s price remains pinned close to zero.[1][10][19][20]

For traders, the main catalysts are the **Hong Kong Observatory’s short-range forecast updates**, thunderstorm warnings, and any late-day rainfall or cloud cover that could suppress the overnight minimum before the settlement cutoff. HKO issued a thunderstorm warning at 6:00 a.m. on 31 July 2026, extended to 11:00 a.m., with squally thunderstorms expected, which matters because local cloud and rain can affect the night’s minimum more than the daytime high.[9] The contract cannot resolve until the Daily Extract is published, so the practical focus is on whether the Observatory’s final archive shows a materially cooler minimum than the usual late-July pattern.[4][10]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Kalshi UK, which mirrors the Polymarket order book directly.

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 UK. 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.

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.