PST to UTC

Studios, game publishers and app makers on the West Coast often launch at a round Pacific hour and translate it for everyone else. "10:00 AM PT" becomes 18:00 UTC in winter and 17:00 UTC in summer; a midnight Pacific release is 08:00 or 07:00 UTC the same day, which is morning in London and evening in Tokyo. Publishing the UTC value alongside the Pacific one saves your global audience a calculation and stops the "PST" in your post being read as UTC−8 in July.

If an announcement covers dates on both sides of a clock change, give each date its own UTC time. A weekly 10:00 AM Pacific stream moves from 18:00 to 17:00 UTC after the second Sunday of March.

Writing a fixed offset like "−08:00" into a config file or database column is a common bug: it is correct only in winter. Use the region name America/Los_Angeles instead, so software applies UTC−7 automatically in summer. Watch out for the POSIX-style names under Etc/, whose signs are inverted: Etc/GMT+8 means UTC−8, the same as Pacific Standard Time.

Pilots departing San Francisco or Seattle file flight plans in UTC as well, so an 11:30 PM Pacific red-eye in winter appears as 07:30Z on the next date. To read UTC back into Pacific time, open UTC to PST.