what time do mail deliver refers to the hours during which the United States Postal Service delivers mail to residential and business addresses. USPS typically delivers mail between 9:00 AM and 5:00 PM, depending on the area and the volume of mail. For e-commerce businesses, knowing when mail is delivered helps plan for package arrivals, and ensure customers receive their orders on time. While USPS has standard delivery hours, it may take longer to deliver mail to rural areas or during busy seasons like holidays.