If your bin is outdoors, it must be shaded. If you are putting worms in a planting bed or a raised be a layer of mulch on top the bed will be helpful in keeping them cool. For compost bins, moist fabric, cooler pads or some other insulating material on top of the pile will help. Compost tumblers are tricky, and I wouldn’t recommend worms for that type of composter. If they are outdoors, keep a close eye on the moisture levels in the bin.
You must keep in mind if you’re using the worms in a compost container, it cannot be a heat compost (thermophilic) pile or it will bake the worms.
If you have a self-contained worm habitat for growing worms, the best idea is to keep it indoors. Keeping in mind that if you feed the worms fruit, you may have fruit flies. Other than fruit flies, bins have no odor and are no intrusion on your living space. Some people choose to keep it under their sink or in their pantries.
Remember, thicker the bedding material (leaves, cardboard, coco peat) in your bin, the safer the worms are. Bedding should be at least 6 inches thick.
If you have any more questions, please don't hesitate to ask me!