Yes, you’ll tend to see flies more during warmer months. Flies become very active beginning in late May. Their peak season is late summer. Their breeding season comes to an end in October and they tend to be much less active when temperatures are less than 45 degrees Fahrenheit. During these colder months, flies are generally in their pupal stage buried 1–6 inches beneath the soil.  After the winter months, they emerge as adult flies and begin their mating cycle all over again.