It sounds like the ashtray has given up the ghost - there's a pin that locates in the mechanism and it breaks, meaning that the tray doesn't close.
It is repairable but is a b****r to do. I;ve done mine and it was a right pain. If it bothers you, you may as well get a new one - it's far easier.
The climate issue is a bit strange though - mine has always only gone down to 18 celcius and up to 29 - to be honest, I wouldn't want it to be any lower than 18 - I never have it any less than 20!
Cheers,
Mike