Recently I've been on a business trip in Germany and I had a temperature problem in my hotel room.
Since it was an attic room without air conditioning the temperature rose to uncomfortable levels during the day and my only solution to sleeping somewhat comfortably was taking a cold shower right before going to bed. (I don't particularily like cold showers).
Are there some things and/or life hacks I can apply when I have to face unpleasant temperatures in a hotel room? This could be things to ask for, buy or just simply do.
Also my example is related to heat but I'd also be interested in a solution to a way too cold room.
Note: I tried opening the windows but in the end it didn't really cool down and I had a couple mosquitos in the room...