Highest temperature in Hong Kong on July 4?

Platform comparison

Market context

On 4 July 2026, the Hong Kong Observatory will record the absolute daily maximum temperature in degrees Celsius, with this market currently pricing a 28°C hit at 0% YES on Polymarket. Traders using USDC on the Polygon network see conditional tokens reflecting near-zero confidence that the peak will reach this threshold, despite the on-chain mechanics allowing precise resolution once the Daily Extract is finalized.

Historical July data frames this probability: July 2024 saw a peak of 34.8°C on 7 July, while July 2018 recorded a mean maximum of 31.8°C, and the city’s hottest month on record in 2023 featured 22 sweltering evenings with minimums above 28°C[6][8][9]. These comparable cases suggest that 28°C is a low bar for Hong Kong in July, yet the current 0% pricing implies the crowd expects either a significantly cooler day or a data anomaly, making the historical warmth a critical lens for reading this outlier probability.

Traders should monitor the Hong Kong Observatory’s Daily Extract publication schedule, which finalises the “Absolute Daily Max (deg. C)” only after data is verified, and watch for any weather bureau announcements regarding unusual cloud cover or monsoon shifts that could suppress temperatures[2][7]. Recent reports confirm July 2023 was the hottest month since 1884, with record hot nights, so any deviation from this pattern in 2026 would be a key catalyst[6]. The resolution depends entirely on the Observatory’s official figure, not forecasts, so the settlement window ending 2026-07-04T12:00:00Z hinges on this single data point.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Hong Kong on July 4? 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

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

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'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.

Do I need to KYC for this market?

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

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.