Yes. Flies overwintering inside a structure can become active when sunlight warms the attic or wall spaces where they are sheltering.
There are many species of flies that, when the weather turns cold, start overwintering in warmer places. This often means homes. While inside, they go dormant for the most part. But when sunlight or high temperatures warm the attic or wall where they live, the insects can start waking up and flying around again.
When you see flies in your home in the winter, it can often look like a new infestation, but that’s probably not the case. Instead, what likely happened is that those flies settled into your home somewhere where they wouldn’t be found. Then temperatures went up and they became active again and started moving toward light. This is why you can sometimes see flies flying sluggishly around windows in the winter. It’s also why this tends to happen less often on colder days.
If flies repeatedly appear only during sunny winter periods and primarily in upper rooms, overwintering insects are a plausible reason why. Persistent fly activity around drains, garbage, or another indoor source may indicate something different entirely.
If you don’t want flies in your home in the winter, your best bet is to prevent them from entering in the fall. Start by inspecting upper windows, siding, soffits, attic vents, and roofline transitions. If you see cracks, seal them with caulk. Replace worn weatherstripping. Be sure to also replace any broken screens or vents if you find them. As a nice bonus, this will also help deter boxelder bugs, stink bugs, and even rodents.
If flies are becoming a problem around your Rockford property, Mosquito Squad of Rockford can help with pest control around the property. Call (815) 324-6061 or request a free quote online.
