An alternative Tube map has been put together which shows which lines are air-conditioned to help Londoners travel during the heatwave.
The map, made by author Geoff Marshall, shows where Londoners can expect to keep cool when moving through the Tube.
Less than half of the Tube network is currently served by air-conditioned trains, covering the Circle, Hammersmith & City, District and Metropolitan lines.
TfL Rail, as well as Northern City, London Overground, Thameslink and tram services also have air conditioning.
It comes as temperatures in London continue to reach more than 30C, after the hottest August day in 17 years was recorded last week in Heathrow and Kew Gardens.
London is expecting a top temperature on Wednesday of 31C, forecasters have said.
Plans for air-conditioned Tubes on the Piccadilly, Bakerloo, Central, and Waterloo and City lines are in the pipeline as part of an overall upgrade, but are at least a decade away.
During previous heatwaves, rush-hour commuters on the London Underground have sweltered in temperatures above the legal limit for transporting livestock.
Cattle, sheep, pigs and goats, must be kept in compartments between 5C (41F) and 30C (86F) for export journeys over eight hours, according to the Department for Environment, Food, and Rural Affairs.
However, there is flexibility of plus or minus 5C to allow for exceptional circumstances.
At the peak of the July 2018 heatwave temperatures reached 35.7C (96.26F) on the Central line, while the Bakerloo, Victoria and Jubilee all were several degrees above the 30C (86F) maximum for transporting cattle, sheep and pigs.
The humidity in some carriages even rose above 60 per cent.
