Worms do best in a bedding temperature range of 12° to 24° Celsius. The air temperature can be higher or lower than this – bedding temperature is generally an average of the air temperature on a given day. So, if it is 4° C at night and 26° C during the day, the average temperature is 15° C and your worms will be fine. They can be kept indoors or outdoors as long as they are protected from bedding temperatures over 85°, freezing cold and direct rain. You can check the bedding temperature with a soil thermometer. More information on maintaining a good temperature for your Nature's Wormery™ can be found here.
You can keep your worm bin inside.
A properly maintained worm composter will not have any offensive odor so keeping it inside should not be a problem. Because of its small footprint, the Nature's Wormery™ can be kept almost anywhere – a closet, in the kitchen, bathroom, living room, garage, or basement.
When you keep your worm bin outside, be conscious of the temperature.
Outside, just make sure that your worm bin is not in direct sunlight or overly exposed to rain and wind. If you do not have an overhang, placing it underneath a leafy tree or a porch can work. If you do keep it outside, you should move it indoors in extreme weather (prolonged excessive heat or cold).