McDonald's typically starts serving lunch at 10:30 a.m. local time Monday through Friday. On weekends, the start time for lunch can vary slightly, usually between 10:30 a.m. and 11:00 a.m., depending on the location. The switch from breakfast to lunch generally happens around 10:30 or 11:00 a.m. since that's when the breakfast menu ends and the lunch menu begins. Times may vary slightly by franchise location, so it's best to check with your local McDonald's for the exact time.