We're lucky. The nighttime low temperatures in the twenties are about as bad as it gets around here, at least for any length of time. But even our kind of cold weather can be real trouble. Remember our "Four P's?" People, pets, plants and pipes need protection from the cold.
Let's start with us. The Centers for Disease Control has a site talking about extreme cold. We don't really count as "extreme" when you see the folks up north with double- digit below zero weather. But our twenties and thirties is enough to do some damage indoors and out. Check the page on staying safe and warm inside, with tips on safely heating your home and caring for folks the cold can really hit hard, the elderly and infants.
Since at some point you'll probably have to go out in the cold, if only from the house to the cold car, check their tips on staying warm enough to survive. It really doesn't take long to do some damage, like frostbite, if you're out in cold, windy weather.
The National Safety Council has some more in-depth information about cold weather first aid. Not a bad thing to check out.
On to the next "P," our pets. The Dog Owners Guide has good tips about all the hazards of the winter season, yes, including antifreeze. It's poisonous, and the kind of bedding to give your pet if you make them stay outside. Your old blankets are not the best option. A small doghouse to get out of the weather, and actually, straw or hay for bedding is best.
The next "P" can be an expensive one. Frozen pipes. Who else but an insurance company, State Farm, would have a site on pipe problems. Think about this. Your typical frozen pipe, when it bursts, spews about 250 gallons of water a day. One day could ruin a room. If you're on vacation when that pipe bursts, much of your house could wind up soaked and spoiled. So check their prevention tips.
If it's already too late, check out My Great Home. They offer several solutions on thawing the pipes, safely, including warnings about what not to do to make sure you don't make the pipe problem worse.