As a German, I want to add that on German trains, "in the summer" implicitly means "without working air conditioning" ;). (Sort-of-jokingly. On ICEs, you're mo

As a German, I want to add that on German trains, "in the summer" implicitly means "without working air conditioning" ;). (Sort-of-jokingly. On ICEs, you're most likely to actually freeze body parts off due to the harsh AC. On local trains, you'll dehydrate due to excessive sweating. There is no middle ground.)