PHP Warning: date(): It is not safe to rely on the system's timezone settings...

Issue

I see the following error in logging and sometimes on the my PHP webpage:

Warning: date(): It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'America/New_York' for 'UTC' for now, but please set date.timezone to select your timezone. in /path/to/myscript.php on line XX