Highest temperature in Hong Kong on July 4?

Platform comparison

Market context

The Hong Kong Observatory will record the absolute daily maximum temperature in degrees Celsius on 4 July 2026, resolving this market to the specific range containing that figure. On Polymarket today, the contract prices "31°C" as the frontrunner at 59% probability, while "30°C" sits at 32%, reflecting a collective view that the peak will hit the upper end of the typical July band rather than the lower ranges[1]. This pricing exists on the Polygon network, where shares are settled in USDC via conditional tokens, meaning the market is currently betting heavily against the 0% implied probability for the lowest tiers and instead targeting the 30–31°C window.

Historical climatology frames this pricing as rational, given that July is Hong Kong's hottest month with average highs around 32°C and daily peaks frequently reaching 30–31°C[5]. Recent records show the city sweltering on its hottest July day ever, with maximums hitting 39°C in Sheung Shui, confirming that extreme heat events are not anomalies but part of the seasonal volatility[10]. The current 59% probability for 31°C aligns with the long-term average of 30.9°C recorded in late July, suggesting traders are correctly weighting the likelihood of a standard hot day over a cooler outlier[3].

Traders must monitor the Hong Kong Observatory's "Daily Extract" release schedule, as the market cannot resolve until the "Absolute Daily Max" is finalized and published[6]. Key catalysts include real-time weather advisories for violent gusts or heat warnings, which recently triggered alerts for maximum temperatures of 34°C[7]. Any official announcement regarding tropical cyclones or sudden shifts in the monsoon flow could drastically alter the final reading, so the dependency on the Observatory's data finalisation remains the critical variable for position management[6].

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

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

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.

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 Polymarket Legit? 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.