Hawaii residents should send first-class and Priority Mail cards, letters and packages by Dec. 19 to ensure delivery to the mainland by Christmas, the U.S. Postal Service said Monday.

For mail to international and overseas military addresses, the date is Dec. 10 for "best chances of reaching their destinations by Christmas," the postal service said in a press release.

"Procrastinators have until Dec. 21 to send their holiday cheer to the mainland via our expedited Express Mail service," the postal service said.

Here are the suggested mailing dates from Hawaii to the following destinations (Express Mail dates in parentheses):

» U.S. mainland, Dec. 19 (Dec. 21)

» Hawaii, Dec. 22 (Dec. 23)

» Guam and Saipan, Dec. 16 (Dec. 20)

» American Samoa, Dec. 14 (Dec. 19)

» Military APOs & FPOs, Dec. 10 (Dec. 16)

» International, Dec. 10 (Dec. 16)

Extended post office hours also were announced, particularly for Oahu’s busiest branches at the airport and Ala Moana Center.

Airport Post Office

Dec. 12: 8 a.m. to 9 p.m.

Dec. 16: 8 a.m. to 9 p.m.

Dec. 17: 8 a.m. to 6 p.m.

Dec. 18: 10 a.m. to 5:30 p.m.

Dec. 19: 8 a.m. to 9 p.m.

Ala Moana Post Office

Dec. 12: 9 a.m. to 5:30 p.m.

Dec. 16: 9 a.m. to 5:30 p.m.

Dec. 17: 9 a.m. to 5:30 p.m.

Dec. 19: 9 a.m. to 5:30 p.m.

Call 800-ASK-USPS or go to usps.com and click on "Find Locations" for hours of operation at specific post offices.