London Heatwave: Final Forecast on When It Will End and Expected Temperatures

The ongoing heatwave in London shows no signs of abating, with the capital poised to endure yet another week of soaring temperatures. Weather forecasts predict a stretch of six consecutive days with temperatures exceeding 30 degrees Celsius, commencing around 2pm today, July 6. It is anticipated that thermometers will remain elevated until Tuesday, July 14, when temperatures are expected to dip below 28 degrees Celsius. Following this brief respite, the city can expect slightly cooler highs of around 27 degrees, accompanied by some rainfall, between then and Sunday, July 19. This shift will undoubtedly provide a welcome break from the fluctuating heatwave that has gripped the city since mid-June, which previously saw temperatures soar to a record-breaking 36.4 degrees Celsius.

Impact of Urban Heat Island Effect

London has been significantly impacted by extreme weather conditions, both last summer and this year, largely due to the Urban Heat Island (UHI) effect. This phenomenon can elevate temperatures in urban areas by as much as 10 degrees Celsius compared to surrounding rural locations, primarily due to the density of buildings. While forecasts from various meteorological services suggest highs of 31 to 32 degrees Celsius in the coming days, the Met Office has indicated the potential for temperatures to reach a sweltering 33 to 34 degrees Celsius from Wednesday, July 8 to Friday, July 10.

In addition to the heatwave on land, meteorologists have reported the emergence of a Category 2 marine heatwave, which poses significant risks for wildlife and marine ecosystems. Sea-surface temperatures along much of the English and Welsh coastlines, as well as in the English Channel and central and southern North Sea, are currently between 1.5 to 4 degrees Celsius above the normal range. Given the ongoing heatwave this week, there will be limited opportunities for these waters to cool, raising concerns about the potential for an ‘extreme’ Category 4 marine heatwave, a phenomenon that is seldom observed in UK waters.

Expert Insights on Marine Heatwaves

Dr Ségolène Berthou, an expert in air-sea interactions, has noted that marine heatwaves around the UK have escalated rapidly in the wake of a recent heat dome, leading to widespread, strong to locally severe conditions. “This marks the third and most intense marine heatwave we have encountered this year,” she explained. “While the warmer sea temperatures have not drastically increased peak temperatures on land, they have hindered night-time cooling and sustained warmth, particularly in coastal regions.”

Looking ahead, with more sunny and calm weather likely to persist into next week, the ocean will have minimal opportunity to dissipate this excess heat. Consequently, the marine heatwave could intensify further, potentially reaching extreme levels in the southern waters. Such conditions would be remarkably atypical for the waters surrounding the UK.

Upcoming Weather Forecast

The weather forecast for the coming days is as follows:

• July 6 – High: 32°C / Low: 17°C, sunny with a gentle breeze
• July 7 – High: 30°C / Low: 17°C, sunny with a gentle breeze
• July 8 – High: 32°C / Low: 20°C, sunny with light winds
• July 9 – High: 32°C / Low: 19°C, sunny with light winds
• July 10 – High: 31°C / Low: 18°C, sunny with a gentle breeze
• July 11 – High: 30°C / Low: 18°C, sunny with a gentle breeze
• July 12 – High: 29°C / Low: 17°C, sunny with a moderate breeze
• July 13 – High: 28°C / Low: 17°C, sunny with a moderate breeze
• July 14 – High: 27°C / Low: 17°C, sunny intervals with a gentle breeze
• July 15 – High: 28°C / Low: 17°C, sunny intervals with a gentle breeze

For those seeking refuge from the heat, a map of locations offering free air conditioning can be found on various local resources. Additionally, subscriptions to daily newsletters will provide the latest updates and information from across London.