Once electricity is out how long will food last in the refrigerator?

The food will stay cold for about four hours if you don't open the door, according to U.S. Department of Health & Human Services. Freezers can keep their contents frozen a little longer—full freezers will be okay for about 48 hours, and half-full freezers are good for 24 hours.

If the power is going to be out longer than that, dry or block ice can keep your food cold until the electricity comes back on. You can make your own ice during winter power outages by filling containers with water and leaving them outside, but don't put your food out in the snow to keep it cold—that's asking for trouble from your local wildlife.