McDonald's generally starts serving lunch at 10:30 a.m. local time on weekdays. On weekends, lunch usually begins between 10:30 a.m. and 11:00 a.m., depending on the specific location. These times can vary slightly based on the restaurant's location and franchise decisions, but 10:30 a.m. is the most common start time for lunch during the week. To be sure of the exact lunch start time for your local McDonald's, it's best to check with that specific restaurant directly.