At 2am it's 19C, still good.

I just got back from a 2 week trip to Germany and suffered through a blistering heat wave. The hotel was very nice but the lack of air conditioning, fans, or even ice cubes was a huge deal. For one thing, you run through clothes much faster than you expected because everything gets soaked with sweat after just a few minutes. Sleeping was difficult because there was not a breath of air even with the windows wide open. The one good thing was that with the heat, you could not get any relief in the hotel room so you had to spend all of your time in outdoor cafes which allowed you to have some enjoyable interactions with the locals. Still the most memorable part of the trip was that it was just so unbelievably hot. With Global Warming accelerating, I think the lack of at least fans will become an issue for summer time travel to Germany.

http://www.youtube.com/watch?v=y2he3gF5uSM
13C / 55F at 6am and lots of rain.