I'll echo what others have said about temperature and intonation. Cold is bad for horns like trumpets, but it's probably worse for bigger horns with more metal. I've also had some rough gigs in the wedding band due to the fact that the tenor sax was flat to the point that he couldn't push the mouthpiece in any further to get it in tune, all thanks to the cold.
Heat will do it too. I did some gigs as an Army bandsman where it was so hot that your my horn felt hot in the hands, and you just kind of hand to live with the idea that the band as a whole was going to be an intonation wreck, and it was never going to lock in.