With weather in the Northeast anything but wintery lately, I'm completely obsessed with cardigans. These lovely little button-down sweaters aren't just for teachers and preppy girls anymore (though they are a preppy fashion essential) - they are stylish, cute and ultra functional.

It's so easy to wear a cardigan, and every girl's wardrobe needs one this season. Here's why:

• They add color & interest to any outfit. Buy a cardigan in a bright color (we love the red trend for fall) to dress up a basic outfit. A plain black tee looks amazing with a colorful cardigan, jeans and some simple jewelry.
• Dress them up or down. Cardigans are great for throwing on for class and staying warm, but are equally awesome to wear at work, to internships, dinner with your boyfriend's conservative parents, etc.
• You'll be prepared for any weather. Throw a cardigan in your tote bag to protect from unexpected cold outside or even air conditioning. You'll look cute and be comfortable no matter what!
• Wear your summer tank tops into fall. All those fabulous summer tank tops you own are good through November with a simple cardigan on top. Hello wardrobe versatility!
• The celebrity style factor. Stars like Jessica Alba, Rachel Bilson and Reese Witherspoon live in their cardigans and pair them with skinny jeans, a scarf, or even a dress and flats.

Where to Buy a Cardigan

Now that you know why you need one, here's where to buy a cardigan. 

Keep in mind that cardigans can wear out fast around the buttons, so it's worth it to spend more on a high-quality cardigan that will last. Also, if you're buying an ultra cheap cardigan, we recommend keeping it buttoned as much as possible to avoid showing shoddy button hole work.

• Urban Outfitters carries lots of cute and trendy cardigans in both basic and unique styles. Plus, the prices are good.
• Gap.com is a great source for all things basic, casual and classic at rock-bottom prices. They have a great cardigan selection!
• J.Crew is the classic choice. Their Tippi cardigan, while a little pricey, is the stuff of legend. You'll have yours FOREVER.
• Nordstrom also stocks high-quality cardigans in tons of prints, lengths, and styles. 
• Forever 21 carries some good options; just don't expect them to last too long and be sure to inspect the button holes to make sure they're well-made.
• H&M is another great source for cardigans of every color at insanely good prices. As with Forever 21, quality issues can be a concern. Don't expect these to last forever but do have fun buying trendy styles.

Thoughts, comments, opinions on this? Post a comment below and let me know what you think!