From a USPS press release:
SAN FRANCISCO, CA — The Postal Service has experienced a drop in walk-in revenue at brick and mortar Post Offices, especially on Sundays. Because of this, the four San Francisco Post Offices with Sunday retail hours will no longer offer Sunday services.
The first Post Office to end Sunday hours will be Macy’s Station at Stockton and O’Farrell, which will make the change effective July 21, 2013. Following Macy’s, Marina Green at 3749 Buchanan will end Sunday hours effective July 28, 2013 then Lakeshore Plaza, 1543 Sloat Blvd. on Aug. 4, 2013 and finally Airport Station, 660 Westfield Road on Aug. 11, 2013.
With nearly 100,000 places to buy stamps, ship a package or renew a passport, nearly 40 percent of the Postal Service retail revenue comes from expanded access locations such as Costco, Office Depot, grocery stores, drug stores, Self Service Kiosks (SSKs), ATMs and usps.com, which is open 24/7.
There are about 32,000 Post Office locations around the country that sell Postal Service products and services. There are more than 50,000 other locations selling postage stamps alone – the top product sold at Post Offices. With the additional shipping provider locations added in, customers have about 100,000 locations and ways to do business with the Postal Service.
Customers can find dozens of locations to purchase postal services within their neighborhoods by visiting usps.com and typing in a ZIP Code. Using a simple drop-down box designating stamps, shipping and packaging, PO Boxes and other services, customers can easily navigate to retail outlets, grocery stores, SSKs and Post Offices, among other options.