Highest temperature in Hong Kong on June 30?

Platform comparison

Market context

The real-world event hinges on the absolute daily maximum temperature recorded by the Hong Kong Observatory on 30 June 2026, specifically whether it falls within a defined range that triggers a "YES" settlement. This single data point, extracted from the official "Daily Extract" once finalized, dictates the market outcome, making the reliability of the HKO’s reporting schedule the primary dependency for any programmatically executed conditional order.

Historical June data frames the current 23% crowd-implied probability as conservative; the highest monthly mean maximum temperature for June in Hong Kong was 32.4°C in 2016, with 2015 and 1938 also recording peaks above 31.7°C[9]. Recent forecasts for late June suggest daytime highs between 27–31°C[4], yet the HKO recently recorded a peak of 34.6°C during the hottest "Mangzhong" on record, indicating that extreme heat events remain possible even as wet weather systems loom[2]. A trader building a bot to monitor this market should treat the 31°C and 32°C ranges as the most likely peaks, as Polymarket data currently assigns 44% and 28% probability to these outcomes respectively[1].

The critical catalyst to watch is the HKO’s warning of a broad low-pressure trough lingering over southern China, which is expected to bring nine consecutive days of rain starting this weekend, potentially suppressing temperatures to 26–30°C[2]. This active weather system, peaking with squally thunderstorms on Sunday and Monday, represents the primary risk to any "YES" position, as heavy showers could rapidly alleviate the intense heat[2]. Traders must monitor the HKO’s daily updates for the "Absolute Daily Max" value, as the market cannot resolve until this specific data point is published in the official climatological extract[3]. The settlement window closes at 12:00 UTC on 30 June 2026, requiring precise timing for any automated execution strategy.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Polymarket App UK, which mirrors the Polymarket order book directly.

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 Polymarket App UK. 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'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.

Do I need to KYC for this market?

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