I always believed that tics are not active in the winter until I read a study by Ball State University on the tics native to Indiana. That study says they are active all winter long but not like during the spring summer or fall. They are not as active and do not have grass and thick weeds to climb on to but they stay pretty much on the ground under the layers of fallen leaves brush and other compose. Another myth according to them which is not true is that tics leap onto you from trees and tall bushes. They climb onto tall grass and other cover and when you brush by they hitch a ride. I don't spray my hunting cloths during the late fall or winter but I still check over everything when I get home outside on the back patio area.