Mosquitoes are notorious for finding their way into homes, often through the tiniest openings. While window screens act as a barrier to prevent insects from entering, mosquitoes can still squeeze through if the mesh size is too large or if there are gaps around the edges. Standard window screens with mesh sizes of about 18x16 or smaller are effective at keeping mosquitoes out. However, it's essential to ensure screens are properly installed and free of tears or holes to prevent these pesky insects from infiltrating your living space.