FedEx and the US Postal Service expect Monday to be their busiest processing day of the year, with an estimated 960 million pieces of mail entering the system. That's nearly double the average daily volume throughout the year. The busiest delivery day is expected to be Wednesday.
Keep in mind, the deadline to send gifts by parcel post is Tuesday to make sure they arrive by Christmas. Saturday is the deadline for Priority Mail and Dec. 23 is the deadline for Express Mail.