Flies survive the winter using several strategies depending on the species. Many flies enter a dormant state called diapause, allowing them to reduce metabolic activity and survive cold temperatures. They seek warm shelter indoors in places like attics, basements, and walls, or find protected outdoor locations such as under bark, leaf litter, or in manure piles. Some flies complete their lifecycle before winter, with eggs or larvae overwintering in protected spots underground or inside houses. Adult flies like cluster flies can also overwinter indoors in a semi-dormant state, sometimes emerging on warm winter days. In summary, flies either overwinter as eggs, larvae, pupae buried underground or in sheltered habitats, or as adults hiding indoors in warm, undisturbed areas until spring.