Snow tires aren't a necessity but the type of rubber is also better at reacting to both going and stopping in colder weather as well as more channels to displace water and snow so it's ideal if you have space to store your summer tires, also with having both you extend the wear of both sets of tires. I really like my general altimax arctics for great snow tires at a good price. On my Subaru it was unstoppable and they're great on my VW. Everyone thinks AWD is the savior but FWD on snow tires will usually be better than AWD on all seasons and also your stopping will be better. If you've never tried to come to a stop in snow or dealt with feeling ABS kick in you really should find an unplowed parking lot and slam in the brakes to get used to what it feels like, you will be amazed how long it can take to stop in snow.