Highest temperature in Hong Kong on July 17?

Platform comparison

Market context

Hong Kong is currently under a broad trough of low pressure, bringing unsettled conditions with heavy showers and squally thunderstorms that are suppressing peak temperatures for today. The Hong Kong Observatory forecasts a maximum of 29°C for Friday, 17 July, with rain likely preventing the city from reaching the higher extremes seen in recent dry spells [1][4]. This immediate meteorological setup explains the market’s current 0% probability for any outcome significantly above 29°C, as the active weather system acts as a direct cooling mechanism.

Historically, July in Hong Kong exhibits a long-term warming trend driven by climate change, with temperatures increasingly leaning towards normal to above-normal levels under El Niño conditions [3]. However, comparable cases where a low-pressure trough dominates the region show that daily maximums often stall near 29–30°C despite the seasonal heat, as cloud cover and precipitation limit solar heating [3][5]. The market’s pricing reflects this specific historical constraint: while the season is hot, the current atmospheric dynamics make a breakout above 30°C unlikely, aligning with the frontrunner outcome of 29°C holding a 37% probability [2].

Traders should monitor the development of the tropical cyclone east of the Philippines, which is projected to approach Hong Kong by Saturday night, potentially bringing further heavy rain and wind that could extend the cooling effect into the weekend [6]. The key dependency is the timing of this system; if the cyclone arrives earlier than forecasted, it may reinforce the low-pressure trough and keep temperatures firmly capped at 29°C or lower [6]. Additionally, watch for any sudden shifts in the anticyclone aloft covering Guangdong, as a weakening of this feature could alter the rain pattern and allow temperatures to rise unexpectedly before the settlement window closes [1].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Hong Kong on July 17? 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.

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.

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.