Highest temperature in Hong Kong on June 20?

Platform comparison

Active sub-markets

Market context

Polymarket has this contract priced at **0% YES**, so the market is currently saying there is no meaningful chance that Hong Kong’s official high on 20 June ends up in the contract’s YES range. For a user holding USDC on Polygon, the practical question is whether the Hong Kong Observatory’s final “Absolute Daily Max” lands in a higher band than traders presently expect; settlement will follow the Observatory’s published daily extract rather than any private forecast or live app reading.

Historically, June in Hong Kong is hot enough that the upper end of the distribution is not trivial: AccuWeather’s June outlook shows daily highs around 88°F to 94°F, while Weather2Travel describes typical June daytime maxima of about 30°C. The Observatory’s own seasonal forecast for June to August 2026 also points to **above-normal temperature**, which matters because prediction markets often trade on whether a day beats the seasonal baseline, not just whether it feels warm in absolute terms. Hong Kong’s recent climate record also shows that extreme June heat is plausible; Earth.Org reported that 2025 included a June absolute maximum of 35.6°C.

For traders, the main catalysts are the Observatory’s day-of weather updates, any thunderstorm or rain-band timing, and how quickly the official daily extract is finalised after the settlement window closes. The contract cannot resolve until the Hong Kong Observatory publishes the relevant data, so any late-afternoon surge, sea-breeze suppression, or rainfall cooling can matter more than the morning forecast. Because the market settles on a one-decimal Celsius reading, even a small shift around a threshold can decide whether conditional tokens pay out in the YES band or not.

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

Where can I trade this market with the lowest fees?

On Kalshi 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.

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 it cost to trade on Kalshi UK?

Zero. Kalshi 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 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.