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Live forecasts update automatically; written guidance last reviewed 20 June 2026 by the BritainNow weather desk. Data from national met services via Open-Meteo.
Live data from Open-Meteo · updates automatically ·
Looking at the live forecast above, London’s 21-day outlook shows a typical mix of mild, unsettled conditions for this time of year, with temperatures hovering near seasonal averages and rain likely at times, especially in the second week.
What’s the general trend for the next three weeks?
For the first week, expect a largely dry and bright start, with highs around 12–14°C and light winds. The middle week turns more changeable, with bands of rain moving in from the west, particularly midweek. The final seven days look cooler, with a chance of overnight frosts and patchy fog, especially towards the end of the period. This is a fairly standard spring pattern for the capital, and you’ll want to keep a brolly handy.
How reliable is a 21-day forecast for London?
While the first 7–10 days are generally reliable, confidence drops significantly after that. Long-range models, like those used for the 10 Day Weather Forecast UK, can indicate broad trends but not precise daily details. The live forecast above is updated regularly, so check back for the latest shifts.
How does this compare to the BBC Weather London 15 day forecast?
The BBC’s 15-day forecast often agrees on the general trend for the first two weeks, but their shorter range means they can provide more precise hourly details. Our 21-day view offers a broader context for planning.
Is there a 28 day weather forecast for London available?
Some long-range models, including those from the Met Office, do offer a 28-day outlook. However, beyond 21 days, the forecast shifts to broad climate patterns rather than day-by-day accuracy, so treat it as a general guide.
Where can I find a 21 day weather forecast London hourly?
Hourly breakdowns are typically only reliable for the first 48–72 hours. For a 21-day view, you’ll find daily summaries more useful. Services like AccuWeather offer extended hourly data, but confidence is low beyond a week.
For more local outlooks, check our guides for Birmingham Weather and Glasgow Weather. For a shorter view, visit the main UK weather hub.