Windows in Jackson swell shut in Pearl humidity, sweat through summer, and leak when a storm blows rain at the meeting rail. A wood sash in a Belhaven plaster wall is not a fogged insulated unit on a northeast ranch. Say which you have, and which wall takes the weather.
In a wet month the sash swells, the latch misses, and someone forces it until the rail splits. In a dry month it shrinks and rattles. That movement is the air and, on some houses, the frame racking with the clay. Condensation runs all summer when the coil cools the room and leaves it wet, and the stool turns dark even with no leak from outside. Haze between panes means the seal is finished. Those are three different calls.
Afternoon rain hits the exposed side and finds a sill that has been caulked instead of flashed. Brick veneer weeps into the cavity. Original ropes and weights fail, and a painted sash looks closed while the meeting rail is open a crack. Basement or low windows behind foundation shrubs stay wet from splash. A later insert in a thick plaster opening leaks at the trim when the fin was buried and the joint was only sealed with a bead.
After the storm, look under the window. Bubbled plaster, a soft apron, or insects on the sill mean water is in the trim. If the bedroom must still open, say so at the start. If several openings on the west wall misbehave and the shaded side does not, say that too. Clay-racked frames can make a sash drag even when the window itself is sound. Mention sticking doors in the same room so the trade does not treat a moving house as a bad hinge.
Call with the neighborhood, the floor, and the wall. Belhaven stair window, Fondren cottage sash, or a ranch picture unit. Wood, metal, or a vinyl insert. Leak, fog, or a sash that will not move. Say whether the stain is new after wind or has been creeping through humid months. The first fact is the opening that let water in or will not close. The rest of the house can wait. Call the number on this page.