This Water Tribe Hoodie from The Last Airbender/The Legend of Korra looks so warm and comfy! I love this design from etsy store RaritysBoutique; it looks awesome. Sadly though Viacom (which owns Nickelodeon) made them take down the Avatar hoodies, so you can’t order one anymore.
On the back is the water element symbol, while on the shoulder you can find the water nation symbol.
The shop also did hoodies for the other elements (Earth Kingdom, Fire Nation and Air Nomad), but those have also been pulled. They still sell a very large range of My Little Pony ones though which also look great (if you My Little Pony).