Highest temperature in Hong Kong on July 4?

Platform comparison

Market context

The Hong Kong Observatory expects daytime highs of 27–32°C for 3–4 July amid partly cloudy skies and scattered rain, setting the real-world baseline for this weather contract [1]. While the crowd-implied probability for a specific outcome is currently 0% YES, the market frontrunner is 31°C at 59%, with 30°C trailing at 32%, reflecting a sharp divergence between the binary odds and the collective view of the most likely temperature range [1]. This misalignment suggests traders are betting on a specific threshold rather than the broader forecast, creating a notable gap between prediction-market implied probabilities and analyst consensus on the contract’s resolution.

Historically, July in Hong Kong has seen mean maximum temperatures of 31.8°C, with the highest monthly maximum recorded at 35.7°C since 1885 [4][6]. The city’s 2025 was its sixth hottest year, with all 12 months warmer than usual and an annual mean of 24.3°C, 0.8°C above the 1991 baseline [7]. These comparable cases frame the current 0% probability as an outlier, given that 31°C aligns closely with the long-term mean and recent heat trends, making the binary odds appear undervalued relative to historical patterns.

Traders should monitor the Hong Kong Observatory’s Daily Extract for the finalized Absolute Daily Max on 4 July 2026, as resolution depends entirely on this published data [1][8]. Recent forecasts from AccuWeather indicate daily highs of 86–96°F (30–36°C) for July 2026, reinforcing the likelihood of temperatures near the frontrunner [9]. No immediate announcements or schedules are expected beyond the standard climatological release, but any deviation from the 27–32°C range could shift odds significantly, especially if scattered rain intensifies or clears unexpectedly.

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 PolyGram, which mirrors the Polymarket order book directly.

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

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.

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.