You may have an emergency car kit of sorts already, with basic items that can be useful regardless of the weather. A first aid kit is a necessity; it should contain bandages, gauze, antibiotic ointment and tape. You should also have a flashlight, and periodically check its batteries to make sure that it's still working. We all have cell phones these days, but they also tend to die when we need them most, so think about getting an instant cell phone battery recharger. Reflective triangles, road flares and a distress sign will alert other drivers of your predicament. Keep a small tool kit equipped with basic tools, such as a crescent wrench and adjustable screwdriver. Make sure you have a tire jack and tire sealant in case of flats. Jumper cables are a must, but consider getting a battery recharger that doesn't require another car.
For bad weather, you'll need to add a few more items that can make all the difference when you're stuck in the snow and ice. These include an ice scraper and small shovel to clear away snow and ice. If your car or truck has the capability to tow, consider stocking a tow rope. An emergency radio can keep you apprised of the weather conditions. If it takes a long time for help to arrive, you'll need a way to stay warm. Keep a blanket or sleeping bag, as well as warm winter clothing, in the kit. Finally, stock some high-energy foods such as nuts or energy bars as well as some water. Some of these items will need to be replaced as necessary. The likelihood of you needing to use your kit is low, but it's better to be safe than sorry.
Driving in foul weather can be a challenge, but you can make your car safer and make it a better experience. Happy driving!