Highest temperature in Hong Kong on June 21?

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Active sub-markets

Market context

The event is the **highest daily temperature recorded by the Hong Kong Observatory on 21 June 2026**, measured in Celsius and resolved from the Observatory’s final “Absolute Daily Max” entry once the daily extract is published. June in Hong Kong can already produce very high maxima: the Observatory’s climate records show June monthly mean maximum temperatures among the city’s warmest on record, and recent summers have delivered individual days above 34°C, including a 36.1°C reading in the city that set a then-record hot day for the year.[3][1][7]

That backdrop helps explain why a **0% YES** market can still carry non-zero weather risk if the day turns exceptionally hot before the settlement window closes. Comparable heat episodes have been tied to subtropical ridge conditions, with local and regional reporting noting 34°C-level summer-solstice heat in Hong Kong in recent years.[6][5] For market reading, the key distinction is that this contract settles on the *highest* reading for the day, not the noon snapshot, so late-afternoon warming or delayed finalisation in the Observatory’s extract matters more than early-day conditions.[2][7]

On access and regulation, the practical question is not the temperature itself but who can legally or operationally participate. German **GlüStV** rules are relevant because event-based contracts can be treated as gambling-like products in Germany depending on structure and distribution, while US **CFTC** reach matters because weather-linked prediction contracts can fall within US derivatives scrutiny if offered to US persons or through US touchpoints. “**No-KYC up to $1,500**” means smaller users may be able to access the market with lighter identity checks until cumulative activity crosses that threshold, but it does not remove geo-restrictions, sanctions screening, or the possibility of additional verification when limits are exceeded.

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

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?

On Polymarket Legal 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 Legal 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.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Polymarket Legal UK triggers a quick verification flow that finishes in minutes.