Email Marketing typically matches your computer's internal clock settings, but selecting a time zone ensures precision! So, it's best to select a time zone prior to scheduling your emails.
Your current time zone setting displays in the Settings area. If there is no time zone set, Email Marketing will tell you what time zone is picked up from your computer.
To make changes, click on that drop down menu, and choose your selection. Make sure to click Save account info when you're finished! :)