The Brief Leaves are falling early in the DMV due to summer water stress. The air is cooler, kids are back in school, but technically, summer isn’t over yet in the Washington, D.C. region. Barnes explained that the D.C. region experienced the driest August on record with just two-tenths of an inch of rain. Why are leaves in the DMV already turning brown and falling? When trees don’t receive enough moisture, they shed leaves early to conserve water.