Monday is the recommended deadline for sending greeting cards and holiday letters that will arrive in time for Christmas. Priority mail can be sent Tuesday and express mail on Wednesday and still make it in time for the holiday, according to the USPS.
Four post offices in San Francisco are open today for people who want to beat the rush to send mail.
The airport post office at 660 Westfield Road is open until midnight, the Lakeshore office at 1543 Sloat Blvd. is open until 5 p.m., the Macy's office at 170 O'Farrell St. is open until 5 p.m., and the Marina Green office at 3749 Buchanan St. is open until 5:30 p.m.
Customers can also skip the trip to the post office with the help of www.usps.com. People can print shipping labels and pay for postage online, and send items in priority mail flat rate boxes.
The 800 million pieces of mail is a 40 percent increase in the average daily volume of 559 million pieces that the USPS handles.