Highest temperature in Hong Kong on June 25?

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Market context

Hong Kong is bracing for its hottest day of the year on 25 June 2026, with the Hong Kong Observatory forecasting above-normal temperatures and high heat and humidity across the region. The market in question tracks the peak temperature recorded that day, yet the crowd-implied probability of a “YES” outcome sits at 0%, suggesting traders believe the temperature will fall outside the specified range. This divergence is stark when compared to sportsbook lines on similar weather contracts, where odds often reflect a 15–20% chance of extreme heat, and analyst consensus leans toward a 30–35°C peak based on seasonal models.

Historical data frames this probability cautiously: June in Hong Kong typically sees daytime maxima around 30°C, with 1.4 days per month affected by tropical storms, yet recent records show spikes to 34.6°C in 2026 and 33.7°C earlier this month[5][6]. The seasonal forecast for June–August 2026 explicitly predicts above-normal temperatures, reinforcing the likelihood of a heatwave[2]. Traders should watch the Hong Kong Observatory’s “Daily Extract” release, which finalises the “Absolute Daily Max” data, and monitor any ENSO-related updates that could shift rainfall or temperature patterns[2]. A recent SCMP report confirms the city’s vulnerability to extreme heat, with hail warnings issued alongside record highs[6].

The settlement window ends at 12:00 UTC on 25 June 2026, and resolution hinges solely on the Observatory’s published data. No other sources or forecasts will determine the outcome. Given the above-normal temperature forecast and recent record-breaking days, the 0% implied probability appears misaligned with empirical evidence, creating a notable arbitrage opportunity for cross-platform odds comparison.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in Hong Kong on June 25? across five venues. We show live odds for Polymarket-based markets (sourced from the Polygon order book); for other venues we list platform attributes, since the comparable contracts are not exposed via a public API on every venue. Every CTA points at Best Prediction Markets — the application we operate, where you trade directly against the Polymarket order book at 0% fees.

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.

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?

Not under $1,500 of lifetime trading volume. Above that threshold, Best Prediction Markets triggers a quick verification flow that finishes in 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.