A summer Tube journey is never exactly great, especially if you're cramming on to a commuter train.
But tomorrow, for one day only, that journey will be a little more bearable, as Transport for London teams up with Danone to give up free Evian to passengers.
For the third year in a row TfL will be handing out bottles to customers travelling on the underground to raise awareness of the need to stay hydrated during the summer.
Mark Evers, director of customer experience, London Underground, said: "Through our partnership with Danone we want to encourage customers to carry water when they travel during the summer, which can help prevent people being taken ill on trains and reduce delays.
"This partnership complements our ongoing investment in cooling the Tube, which includes improving ventilation systems at our stations and introducing new air conditioned trains, which will serve 40 per cent of the Underground network by the end of this year."
Near 250,000 bottles will be given out tomorrow in support of the London Underground's effort to "cool the network".
To date a number of measures have been introduced through a Cooling the Tube programme including; air conditioned trains on the Metropolitan, Circle, Hammersmith and City and District lines, upgraded station ventilation and portable fans installed in ticket and concourse areas.