Highest temperature in Hong Kong on June 30?

Platform comparison

Market context

Hong Kong is currently sweltering through its hottest day of the year, with the Observatory recording a peak of 35.6°C, a figure that starkly contrasts with the 17% crowd-implied probability for a high temperature exceeding 31°C on 30 June 2026. This market on Polymarket, settled in USDC on the Polygon network via conditional tokens, is pricing the contract today at a level that suggests traders expect a significant cooling event, despite the current extreme heat. The on-chain mechanics allow for precise betting on the specific temperature range, with the resolution source being the Hong Kong Observatory’s finalized "Absolute Daily Max" data once published in the relevant "Daily Extract".

Historically, June daily maxima in Hong Kong range from roughly 29°C to 34°C, depending on synoptic conditions, as noted in recent climate analyses [8]. The highest monthly mean maximum temperature recorded in June was 32.4°C in 2016, with 2015 following closely at 32.3°C [9]. However, the current record of 35.6°C is an outlier, and forecasters predict a broad trough of low pressure will linger over southern China, bringing nine consecutive days of rain that will alleviate the intense heat [2]. This active weather system, peaking with heavy showers and thunderstorms on Sunday and Monday, is expected to drop temperatures to a cooler range of 26 to 30°C, directly challenging the current market odds [2].

Traders should closely monitor the Hong Kong Observatory’s weather announcements and the scheduled arrival of the low-pressure trough, which is the primary catalyst for the anticipated cooling [2]. The dependency on the finalisation of the "Daily Extract" data means the market cannot resolve until the official figures are published, adding a layer of uncertainty regarding the exact timing of the settlement [3]. Recent news from The Standard highlights the forecast of severe squally thunderstorms and localized thunderstorms persisting into Tuesday and Wednesday, which will further suppress temperatures [2]. This weather pattern is the critical factor that traders must watch to assess the validity of the current 17% probability for a high temperature above 31°C.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Hong Kong on June 30? 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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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 UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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.

Do I need to KYC for this market?

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