You may think that because you don't see much of indoor pests in the winter that they aren't much of a problem. Cold weather does indeed slow down the breeding rate of common culprits such as fleas, moths and bedbugs, but they certainly don't disappear! In fact our centrally-heated homes and offices protect them from freezing conditions that might normally kill them, so they can certainly be a nuisance at any time of year.
Obviously we spend more time indoors in the winter, so pests that feed off ourselves and our pets, such as fleas, actually have more time to feed and spread themselves around during the winter months. Rodents and cockroaches are also still active at this time of year; cockroaches in particular are hardy souls who can survive for a very long time on virtually nothing - possibly in your kitchen!
Pest controllers such as ourselves know that there's no let-up in our work during the winter; we're just as busy as during the summer, and winter is actually a great time to take action to prevent pest problems becoming a serious issue when springtime comes.