Highest temperature in Hong Kong on June 30?

Platform comparison

Market context

Hong Kong is bracing for its peak June heat as the Hong Kong Observatory tracks daily maxima that historically range from 29°C to 34°C, depending on synoptic conditions[7]. The current crowd-implied probability of 13% for a specific temperature range reflects the rarity of extreme highs in late June, yet historical records show that temperatures can breach 35°C during intense heatwaves[1]. For instance, in 2023, Hong Kong experienced its hottest summer on record, with a maximum of 36.1°C breaking the 1963 record[9], while June 2016 saw the highest monthly mean maximum of 32.4°C[8]. These comparable cases suggest that while 13% seems low, it is not negligible given the potential for sudden shifts in weather patterns.

Traders should monitor the Hong Kong Observatory’s upcoming "Daily Extract" releases, which will finalize the "Absolute Daily Max" data for 30 June 2026[1]. Recent warnings from the Observatory about extreme heat and impending hail underscore the volatility of current conditions[5]. Additionally, the shift in synoptic conditions could push temperatures beyond the typical range, making it crucial to watch for announcements regarding heatwave advisories or rainfall forecasts[6]. The on-chain mechanics of Polymarket, including USDC settlements on Polygon and conditional tokens, ensure that prices will adjust dynamically as new data emerges, reflecting real-time market sentiment on the likelihood of extreme temperatures.

The settlement window ends on 30 June 2026 at 12:00 UTC, meaning the market will resolve once the Observatory publishes the finalized temperature data[1]. Given the historical variability and recent heat warnings, the 13% probability may shift as the day progresses, especially if synoptic conditions intensify. Traders must remain attentive to the Observatory’s updates, as even a one-degree shift could significantly alter the outcome[7]. The interplay between historical data and current forecasts creates a complex landscape for prediction markets, where precision and timing are paramount.

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 PolyGram, which mirrors the Polymarket order book directly.

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 PolyGram. 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.

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.

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.