Highest temperature in Hong Kong on July 17?

Platform comparison

Market context

Hong Kong’s highest temperature on 17 July 2026 is the real-world event this contract tracks, with the market currently pricing the 28°C range at 53% probability and 29°C at 23% [1]. On Polymarket, traders use USDC on Polygon to buy conditional tokens representing each temperature bracket; the zero per cent implied probability for a “YES” outcome on any single range reflects the multi-outcome structure, not a belief that no heat will occur. The settlement window closes at 12:00 UTC on 17 July 2026, once the Hong Kong Observatory finalises its Daily Extract.

Historically, mid-July highs in Hong Kong cluster between 28°C and 32°C, with 28°C appearing frequently in recent summers under typical maritime influence. The current 53% weighting for 28°C aligns with that baseline, suggesting the crowd sees no extreme heatwave catalyst yet. Comparable cases from 2023–2025 show similar distributions, where 28°C often led the probability stack unless a strong southerly flow or urban heat anomaly pushed readings higher.

Traders should monitor the Hong Kong Observatory’s daily weather bulletins and the scheduled release of the Daily Extract, which publishes the Absolute Daily Max once data is verified. A sudden shift in the 24-hour forecast for southerly winds or cloud cover could alter the implied probabilities before settlement. No major announcements are expected in the next hours, but the Observatory’s climatological page remains the primary dependency for resolution [1].

Sources: 1

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 Polymarket Scam?. 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.

Do I need to KYC for this market?

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