Using the underground in London recently, with the high temperatures there have been, has been a steam bath nightmare and like everyone else, I carried a bottle of water.
The best place to travel in these sweat tubes is at either end of the carriage, if you can bear to let seats go and stand for the major part of a journey. Windows can be opened which allows a strong air flow through, albeit a warm one, that revives ones flagging energies. Never mind sagging knees, they become very secondary! U-(
Advisory announcements were made over the tannoy systems about self-help and seeking assistance if feeling unwell, and what not to do, such as not alerting emergency help between stations, in tunnels etc. The announcements were not a lot of use in the span of their delivery as there was too much interference from the wonderfully regular arrival of trains, at least that was so on the lines I was using. You could just make out the full pattern of advice after about three or four journeys or changes of line. Goodness knows what, if anything, foreign visitors made of these fractured pronouncements.
One evening many stations were closed simultaneously, though temporarily, or a few were closed for the duration of the night, because of flash flooding caused by tropical storms and torrential rain. I hit the disruption on the return journey. The threatening skies (seen when overground) and the forks of lightening were quite exciting. I did not get soaked, I experienced a barely noticeable dash of water and my bright rainbow-coloured umbrella did not see the light of day or the darkened skies of the night time.
The following day was noticeably fresher for a short while then the electric stormy tension began to build up again very quickly, though not to the same disruptive levels as seen the day before.