Highest temperature in Hong Kong on June 30?

Platform comparison

Market context

On 30 June 2026, Hong Kong faces a critical real-world weather event: the daily maximum temperature recorded by the Hong Kong Observatory, which will determine the outcome of a prediction market on whether the heat exceeds a specific threshold. With crowd-implied probability at 12% YES, traders are betting against extreme heat, yet the seasonal forecast from the Hong Kong Observatory explicitly warns of above-normal temperatures for June through August 2026, citing ENSO status and climate models as drivers [2]. This divergence between market scepticism and official meteorological guidance creates a notable odds gap when compared to sportsbook lines that often price in higher heat probabilities for late June in tropical zones.

Historical data frames this 12% probability as potentially too low, given that Hong Kong recently recorded its hottest day of the year so far at 34.6°C on a Friday in June, accompanied by hail warnings due to extreme convection [7]. Previous years show June highs frequently reaching 31°C to 32°C, with the New Territories hitting 37°C during recent extreme heat warnings [5][1]. If the market continues to underprice the likelihood of temperatures exceeding 32°C, traders should watch the Observatory’s daily extract releases for the “Absolute Daily Max” figures, which finalise data only after publication [1]. The catalyst for a shift in odds will be the official confirmation of the daily max, as delays in the “Daily Extract” could temporarily obscure the true temperature range until the settlement window closes at 12:00 UTC on 30 June 2026.

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

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.

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.