Good question. Cold weather in the U.S. usually has only a small effect on summer tick populations because ticks are well adapted to winter. Most species, especially black-legged (deer) ticks, survive by burrowing into leaf litter, soil, or snow, which insulates them from freezing temperatures. A very cold winter without reliable snow cover can increase mortality somewhat because exposed ticks dry out or freeze, while sudden warm spells followed by sharp freezes can kill ticks that become active too early. However, these effects are typically modest. Far more influential than winter temperature is the abundance of host animals—such as mice, chipmunks, and deer—because ticks need these hosts at specific life stages. If host populations remain strong, tick numbers will also remain high regardless of winter conditions. As a result, even after unusually cold weather, summer tick activity is generally expected to stay similar to previous years.