I look at the debug.log file a lot while developing, and having all the timestamps in UTC drives me crazy! How can I get them to display in local time? I have my php.ini 'date_timezone' value set to 'America/Los_Angeles' already.
What is the time zone setup in your admin -> settings -> general page? WordPress overrides & kind of disregards php's timezone & uses this own settings , if haven't set this - default is UTC+0
Update: according to https://core.trac.wordpress.org/ticket/39595 - wordpress has forced this to be UTC