Highest temperature in Hong Kong on July 20?

Platform comparison

Market context

The market tracks the peak Celsius reading recorded by the Hong Kong Observatory on 20 July 2026, resolving to the specific range containing that absolute daily maximum once the official “Daily Extract” is finalized. With the settlement window closing at 12:00 UTC on the event date and the current crowd-implied probability for a YES outcome sitting at 0%, the data suggests the market expects the temperature to fall outside the defined winning bracket, likely due to an anticipated lack of extreme heat or a specific range mismatch.

Historically, Hong Kong’s July highs typically range between 31°C and 34°C, with the absolute record for the month reaching 36.1°C in 2017[1]. A 0% probability implies the market believes the 2026 reading will not breach the upper threshold of the offered range, aligning with recent years where scattered cloud cover and sea breezes often cap temperatures below 33°C[2]. Programmatic traders should backtest this against the last decade’s “Absolute Daily Max” CSV feeds to identify if the current range is statistically improbable before the data lock.

Key catalysts include the official publication schedule of the Hong Kong Observatory’s daily climate data, which usually finalizes within 24 hours of the event date. Traders monitoring conditional orders must watch for real-time updates from the Observatory’s open data API, as delays in the “Daily Extract” release can stall settlement. While no specific weather announcement has altered the 0% stance recently, the dependency on the finalised CSV resource means the market remains inert until the authoritative figure is published, requiring automated bots to poll the API endpoint for the exact decimal value[1].

Sources: 1 · 2

Methodology

We track Highest temperature in Hong Kong on July 20? 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.

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.

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.