I have a table http://sqlfiddle.com/#!2/c7c85/1 having timezone and timezone_offset field into it,where timezone_offset field is in seconds, i need to update the invite_limit for all the users at midnight(when it strike midnight in user timezone) accordingly of their timezone,I know i can run a cron job scheduled to be run at midnight of each day which will execute a script to update the DB. The problem i have is users are from different timezones i need to update the field at stroke of midnight per user basis.
User's last visit timestamp should do the trick here. If it's older than user's last midnight time then reset invite_limit (and visit time as well if you'll use it for this purpose only).