I wouldn't advise cleaning at 60 degrees to often as over time it will weaken the glass,even in the summer with water to hot you can damage the glass,big patio glass doors have been known to go bang and shatter when the temp drops later in the year all of a sudden. I've known this happen to other cleaners and they use very hot water, to clean with. In my experience you are safe with 45-50 degrees I've never had one to bang on me on or off the job.