Highest temperature in Hong Kong on July 4?

Platform comparison

Market context

Hong Kong is poised for a hot, partly cloudy start to 4 July 2026, with daytime highs forecast between 27–32°C, yet the market currently assigns zero probability to any outcome below 31°C, a sharp divergence from recent collective pricing that favoured 31°C at 59% and 30°C at 32% just hours ago[1]. This sudden reset suggests traders have re-evaluated the likelihood of a cooler spell, possibly reacting to updated cloud-cover models or overnight rainfall signals that could suppress temperatures, even as the Hong Kong Observatory maintains its standard July outlook[1].

Historically, Hong Kong’s July highs cluster around 28–32°C, with the average high at 29°C (86°F) and a long-term warming trend underpinning above-normal temperature chances this season[2][4]. Past El Niño years, including the developing event expected by late summer 2026, typically push temperatures higher, making a sub-31°C outcome less common but not impossible if heavy cloud or rain intervenes on the night of 3–4 July[4][6]. The current 0% pricing thus appears to overstate confidence in a warm day, ignoring the historical volatility that has occasionally delivered 30°C or lower in similar conditions.

Traders should monitor the Hong Kong Observatory’s 4 July “Daily Extract” once finalized, which will publish the absolute daily maximum temperature to one decimal place[1]. Key catalysts include any overnight rainfall event from 3–4 July, which could suppress the minimum toward 25°C and potentially lower the daytime peak, as well as updated cloud-cover forecasts from the Observatory’s multi-model consensus system[6][9]. A sustained rain event, as noted in recent analysis, remains the primary risk to the market’s warm-day assumption[6].

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

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.

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.

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 Prediction Today 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.