Highest temperature in Hong Kong on June 21?

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Active sub-markets

Market context

Hong Kong’s highest temperature on 21 June will be the Hong Kong Observatory’s **daily maximum in degrees Celsius**, published later in the final Daily Extract rather than in real time. The market’s 0% crowd-implied YES suggests traders are assigning essentially no chance to the selected outcome band, so the practical question for a programmatic setup is whether the published “Absolute Daily Max” lands above any threshold you are modelling, not whether midday readings are warm.[7][4]

The historical frame is that Hong Kong can produce very high June maxima, but the distribution is still sensitive to the exact synoptic pattern on the day. The Observatory’s June climatology shows monthly mean maximum temperatures in the low 30s °C, with recent Junes among the warmest on record, while reporting elsewhere has documented individual June days above 34°C and even 36.1°C in a separate hottest-day event.[2][1][5] A market priced at zero often reflects either a narrow temperature bucket or an expectation that the upper tail is being underweighted by the crowd, which matters if you are using copy-trading or conditional orders that trigger only on a specific range.

The main catalysts are the Observatory’s afternoon temperature updates, any very hot weather warnings, and the timing of the post-event Daily Extract, because resolution depends on the final published figure and not on live estimates.[7][4] Traders automating this market would typically watch Observatory bulletins, compare the intraday forecast against the settlement band, and avoid assuming resolution until the archive entry is finalised. Recent reporting has shown how quickly Hong Kong can swing into record heat when a subtropical ridge dominates, so a late-day spike remains the key dependency rather than the morning reading.[8][6]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Hong Kong on June 21? 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

Where can I trade this market with the lowest fees?

On Polymarket Review UK, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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 does it cost to trade on Polymarket Review UK?

Zero. Polymarket Review UK routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

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.