Highest temperature in London on June 25?

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Market context

The real-world event is the highest temperature recorded at London City Airport on 25 June 2026, with the market currently pricing a 1% chance that the temperature exceeds the upper threshold of the resolution range. Historical data shows London City Airport frequently experiences June highs between 25°C and 35°C, with extreme heatwaves pushing temperatures to 37°C or higher in recent years. For instance, Wednesday 24 June 2026 saw a maximum of 37°C at the station, while Thursday 25 June is forecast to reach 31°C, suggesting the current 1% probability may be overly conservative if the heatwave persists or intensifies unexpectedly [1].

Traders should monitor official Met Office updates and Wunderground hourly records for any sudden shifts in temperature trends, particularly if cloud cover breaks or wind patterns change before the settlement window closes. Recent forecasts indicate a 30% chance of rain at 6am on 25 June, which could suppress peak temperatures, but a high pollen count and very high UV index suggest strong solar heating if skies clear [1]. Additionally, the NW3 Weather report for 23 June recorded a maximum of 33.9°C, confirming that sustained heat is possible in this period, making the 1% YES probability a potential mispricing if the heatwave continues [8]. Watch for any sudden announcements regarding weather anomalies or station-specific data corrections that could alter the resolution outcome.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote (Polymarket), four reference venues with their key attributes, and a single execution path — every trade button routes to Champions League Prediction, which mirrors the Polymarket order book directly.

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 Champions League Prediction, 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 Champions League Prediction?

Zero. Champions League Prediction 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.