Do your temperatures generally go with the weather forecast ? Or are you usually a few degrees above? I would call it as I see it. 42 will not harm them, but be sure to start withholding water now because they will go dormant quickly with those temperatures.
Good luck!
If it's not too much hassle, place them in a protected area (under the eaves of the house or in the unheated greenhouse), the few degrees difference will help.
