Highest temperature in Hong Kong on June 20?

Platform comparison

Active sub-markets

Market context

The real-world event is the daily peak heat recorded by the Hong Kong Observatory on 20 June 2026, measured in degrees Celsius to one decimal place. Historical data frames the current 0% crowd-implied probability as a misreading of seasonal extremes. Long-term averages show daytime maximums typically reach 30°C in June, with high heat and humidity persisting throughout the month[1]. However, recent records contradict the assumption that such temperatures are impossible; Hong Kong broke 20 weather records in 2025, including a June absolute maximum of 35.6°C[6]. The seasonal forecast for June–August 2026 explicitly predicts above-normal temperatures for the region, driven by current ENSO status and climate models[3]. A power-user evaluating this market programmatically would note that the 0% probability ignores the statistical likelihood of a heatwave exceeding standard averages, especially given the forecasted temperature anomaly.

Traders must monitor the Hong Kong Observatory’s "Daily Extract" publication schedule, as the market cannot resolve until the "Absolute Daily Max" is finalized and published[7]. The immediate catalyst is the weather pattern for 20 June 2026 itself; current reports for that date indicate a sunny day with urban maximums around 32°C[4]. While tropical storms affect roughly 1.4 days in June on average, the prevailing forecast suggests normal to below-normal rainfall, increasing the risk of sustained high temperatures[1]. A conditional order strategy would depend on real-time feeds from the Observatory’s regional weather updates, which are refreshed hourly[9]. The dependency is strict: without the official data point in the Daily Extract, the market remains inert, making the timing of the publication a critical variable for settlement.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Hong Kong on June 20? on the five venues with material liquidity for prediction markets. Live odds come from the Polymarket Polygon order book — the only source that ships real-time data under an open licence. For Kalshi, Betfair and Manifold we list platform attributes (fee, KYC, settlement, payment) instead of fabricated odds, because their APIs use non-comparable contract definitions.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Is this market available outside the US?

Polymarket Review UK is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

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.

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.