I play a regular outdoor gig throughout the Summer here in the UK which has my trio set up under a band stand with open sides but overhead cover. I have recently purchased a tube amp and it got me thinking if outside playing can damage a tube amp. The gigs are May - September and many of them are in the evening finishing at 10pm. I have read many times about letting a tube amp reach room temperature before turning it on and letting it cool down before taking out into the cold. The weather on some of these gigs can get quite cold when the sun goes down and I can remember from recent years occasional dampness in the air. Will it be harmful to my tube amp in these situations or is it only winter type cold conditions that will cause problems? The soft case that came with the amp head is very padded so I am thinking that it will help to put this on when I have turned off my amp. Cheers!