PSt

Pacific Standard Time (PST) is a time zone used in parts of North America during the standard time period. It is based on Coordinated Universal Time (UTC) minus 8 hours (UTC-8). During spring and summer, many locations observe daylight saving time, switching to Pacific Daylight Time (PDT), UTC-7. The zone covers the western United States and Canada, and parts of western Mexico, including major cities such as Los Angeles, San Francisco, Seattle, Vancouver, and Tijuana. The dates for switching between standard and daylight time are determined by regional and national governments and may vary by year.

PST, as a file format, refers to the Personal Storage Table used by Microsoft Outlook and related programs. A PST file stores local copies of email messages, calendar items, contacts, tasks, notes, and other data. It is created for POP3 or IMAP accounts, or for archiving older mail. PST files can be password protected and encrypted. The format has two generations: ANSI PST (older, with a 2-GB limit) and Unicode PST (newer, with larger capacity). Large or aging PST files may become corrupted, in which case tools such as Outlook's repair utility (scanpst.exe) or third‑party programs are used. Regular backups and proper data management are recommended.

Other uses of the PST acronym exist in various fields, but the two meanings above are among the most widely encountered. In the context of a given article, the intended meaning is usually clear from surrounding text.