The postal service has issued a useful guide to SouthCoast residents to help us know when we should ship packages to make sure they arrive before Christmas.

Contrary to popular belief, there is no longer a "busiest day of the year" for the post office. Now that online shopping is so popular, the post office's "busiest day" has morphed into the "busiest time." Beginning the week of December 9, customer traffic is expected to increase, with the week of Dec. 16-22 predicted to be the busiest mailing, shipping and delivery week.

The best practice is to avoid shipping anything in the two weeks before Christmas, although we all know that would be extremely difficult.

One extremely convenient feature of the post office is that customers will no longer need to leave their homes to ship their packages. This task can now be done at usps.com. The busiest online day? That is expected to be December 16. More than 8.5 million people will likely visit usps.com to ship holiday gifts to friends and family.

Here are the deadlines to ensure your gift will arrive before Christmas morning when mailed from the SouthCoast of Massachusetts.

December dates:

6th   — APO/FPO/DPO (all ZIP Codes) USPS Retail Ground® service

9th   — APO/FPO/DPO (ZIP Code 093 only) Priority Mail® and First-Class Mail®

11th — APO/FPO/DPO (all other ZIP Codes) Priority Mail and First-Class Mail services

14th — USPS Retail Ground service

18th — APO/FPO/DPO (except ZIP Code 093) USPS Priority Mail Express® service

20th — First-Class Mail service (including greeting cards) and first-class packages (up to 15.99 ounces).

21st — Priority Mail service

23rd — Priority Mail Express* service

*Air/Army Post Office/Fleet Post Office/Diplomatic Post Office and domestic addresses.