There are several items that you will need for the early and late weeks of your hike that will not be necessary during the warm summer months.
•A sleeping bag rated to 20 degrees or less. You can also get a sleeping bag liner and use it along with your summer sleeping bag for extra warmth.
•An extra layer on top. Bring an extra fleece for the first leg of your hike. Another great option is a “puffy jacket.” It’s just a down or synthetic filled jacket that will keep you very warm.
•Bring an extra layer for the bottom. A pair or long johns or a full length pair of running pants should do just fine.
•Extra socks. For the really cold nights, you’ll want to layer two pairs of socks. You probably won’t want to sleep in the sweaty/ wet socks you hiked in all day either.
•A beanie. It does wonders to trap your body heat on cold and windy days.
•Have enough fuel. Your fuel canister will get used up faster in colder temperatures.
Be sure not to mail your cold weather gear home too early. During my hike, we had two weeks of warm weather and sunshine. A lot of hikers sent home their cold weather gear in Irwin, TN. Well right after Irwin, it snowed and the temperture dropped.
A good place to mail cold weather gear home would be Damascus, the first town in Virginia. Have it sent back to you in Hanover, New Hampshire; right before the White Mountains.