Highest temperature in Hong Kong on July 4?

Platform comparison

Market context

The underlying event is the peak daytime heat recorded by the Hong Kong Observatory on 4 July 2026, measured in degrees Celsius to one decimal place. Historically, July is Hong Kong’s hottest month, with daytime temperatures routinely exceeding 30°C and average highs around 31°C[1][3]. Record-breaking days have pushed maximums to 39°C in the New Territories, while the city observatory itself has logged 36.1°C, surpassing the 1963 benchmark of 35.5°C[7][8]. Given this thermal ceiling, a 0% crowd-implied probability for any specific range suggests the market may be mispricing the likelihood of extreme heat, or the range in question is implausibly low for Hong Kong’s July climate.

A power-user approaching this programmatically would monitor the Hong Kong Observatory’s Daily Extract for the finalized Absolute Daily Max, treating the 12:00 UTC settlement as a hard dependency[5]. Key catalysts include the probability of significant rain on 4 July, which is currently rated high and could suppress peak temperatures, alongside sustained southerly winds averaging 4.8m/s that typically drive heat accumulation[1][5]. Traders should also track real-time updates from the Observatory’s climate portal, as recent years show July frequently setting new records for hot days, with temperatures reaching 33°C or higher[9]. The resolution hinges entirely on the official data release, making the timing of the Daily Extract publication the critical execution point for conditional orders.

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

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 Kalshi Fees. 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 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.

Do I need to KYC for this market?

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