With many Tube lines totally free from air-conditioning, commuting this week is going to be a struggle.
But which London Underground lines should you try to avoid on hot days?
What are the hottest London Underground lines?
Top of the list for sweltering Tube lines is the Bakerloo line.
According to an Freedom of Information request put out by the Gizmodo website in 2016, TfL revealed that the Bakerloo line had an average temperature of 27C.
In 2019, thermal imaging company Flier also predicted the Bakerloo could reach a sweltering 42°C,
Coming in second was the Central line with an average temperature of 26.1C, while the Northern line came in third with a sweltering average temperature of 25.2C.
Which are the coolest underground lines?
According to TfL’s 2016 figures, the District, Circle, Hammersmith & City, and Metropolitan lines were the coolest, each with an average temperature of 18.5C.
Those lines all have modern trains with air conditioning.
The London Overground and new Elizabeth line also have precious air con.
Why is the Central line so hot?
The Central Line is one of the hottest tube lines because of its age and depth beneath the ground.
It is one of the oldest lines in London and was opened as The Central Railway in 1900 with early extensions carried out in 1920 and in the 1940s.
The line is a deep-level tube which means it is at least 20 metres underground and travels through two small tunnels to reach each station.
This compact space and lack of ventilation means the heat generated isn’t able to disperse and therefore it stays contained.
The old design of the tunnels makes it difficult to create enough extra ventilation to have a big effect.
Full list of average Tube line temperatures (TfL figures 2016)
- Bakerloo 27C
- Central 26.1C
- Northern 25.2C
- Victoria 24.1C
- Piccadilly 23.2 C
- Jubilee 22.9C
- Waterloo & City 22.2C
- District, Circle, Hammersmith & City, and Metropolitan 18.5C