Worm bins can be used indoors all year round, and outdoors during the milder months.
The advantage of mobile bins is that they can be moved when weather conditions change.
Indoors, basements are excellent locations (warm, dark and dry), but any spare space can be utilized, so long as temperatures are between 40-80 degrees F.
We know dedicated worm composters who have convenient kitchen counter worm bins.
Outdoors, bins can be kept in sheds and garages, on patios and balconies, or in the yard. They should be kept out of hot sun and heavy rain. If temperatures drop below 40 degrees F., bins should either be moved indoors, or well insulated outdoors.
Source City Farmer