Neoscona crucifera
(Hentz Orb-weaver)

She’s Neoscona crucifera or N. domiciliorum. Either way she’s an orbweaver. Windows provide good frames for the webs and insects are drawn to the light. It’s a good spot for a spider that eats flying insects. Orbweavers eat and rebuild their webs every day, so if the web gathers dust or debris – it’s just temporary.