Windows in San Antonio take a long west sun, then hail, then rain that exploits whatever the hail loosened. Glass bakes. Seals fail and panes fog. A storm chips a light or cracks a sash, and the downpour that follows finds a sill that was already tired. Sprinkler overspray, heavy with mineral, spots the outside of the glass and is not a seal failure. Sort those marks before you order a houseful of units.
Fog between panes means the seal is done. A crack from a chip is impact. Water on the stool only after a cloudburst is flashing, a clogged weep, or a frame joint that opened in the heat. Condensation on the room side of a cold morning is rarer here than in a freeze-prone city, so do not assume every wet sill is indoor air. Wipe a spot and watch whether the water returns from the weather. That test is the whole diagnosis.
Openings in stucco and stone, common in older houses, crack at the joint when a new unit is forced in. Ask about the rough opening, the sill pan, and the flashing, not only the size of the glass you see. King William, Monte Vista, and other older blocks often have thick walls and trim that a stock replacement will not respect. Newer houses with big west glass have a heat problem even when every seal is intact. Say which house you have.
Screens shredded by hail and locks that no longer meet are straightforward. A frame twisted by impact is not a glass-only repair. Mineral etched into the exterior from irrigation is a cleaning or a glass question, not a storm claim. Photograph the crack, the fog, and the exterior joint before anyone caulks it. Caulk over failed flashing just hides the path the next downpour will use. Mention if the same storm cracked tiles overhead, because the leak may be the wall, not the window.
Count the units that fog, crack, or leak in rain, and name the west wall if the heat is part of the complaint. Say stucco, stone, or brick. Have the address ready. Ask for glass repair or a full unit in a flashed opening, matched to what actually failed. Call the number on this page.