Highest temperature in London on June 23?

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Market context

London City Airport is currently tracking a southerly flow with 88% humidity and falling pressure, conditions that have pushed the market’s implied probability for a 32°C or below maximum to 100% on 23 June 2026. In the last 24 hours, the Met Office confirmed Kew Gardens hit 26.6°C, the hottest day of the year so far, yet this remains well below the 32°C threshold that traders are now treating as a certainty. The surge in confidence stems from a lack of high-pressure systems forecast to arrive before the settlement window, which closes at 12:00 UTC on 23 June 2026.

Historical data for late June at EGLC shows typical highs between 22°C and 26°C, with only rare heatwaves pushing above 30°C. The 2022 UK heatwave saw temperatures exceed 40°C, but such events require sustained continental airflow and clear skies, neither of which are present in current models. The current 100% probability aligns with the pattern of the last decade, where June 23 maxima have consistently stayed under 30°C, making the 32°C ceiling a statistically robust anchor for pricing.

Traders should monitor the Met Office’s 7-day forecast updates and any sudden shifts in the southerly wind direction, which could introduce warmer air from the continent. A key catalyst is the National Weather Service’s hourly METAR data for EGLC, which will confirm real-time temperature trends as the settlement window narrows. Recent reports from Sky News highlight the Met Office’s role in validating extreme temperature claims, so any discrepancy between Wunderground and official Met Office readings could trigger volatility. Watch for announcements on high-pressure system movements from the European Centre for Medium-Range Weather Forecasts, as these will determine whether the 32°C threshold remains a safe bet.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in London on June 23? across five venues. We show live odds for Polymarket-based markets (sourced from the Polygon order book); for other venues we list platform attributes, since the comparable contracts are not exposed via a public API on every venue. Every CTA points at Prediction Today — the application we operate, where you trade directly against the Polymarket order book at 0% fees.

Resolution & payout

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On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

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