Hi Jeanette! When you schedule a mailing to send at 6 a.m., it pulls that time from your account’s time zone. (You can check your time zone by clicking the gears icon at the top-right and choosing Settings & billing.)
If you’re in Central and know that most of your recipients are in Eastern, you could schedule your mailing based on what time it is for them. But there isn’t a way to know which time zone they’re in and send the mailing and the appropriate times.
I send emails to recipients from the East Coast to Hawaii. The problem here is that if I schedule one for 9am ET, California receives it at 6am and Hawaii receives it at 3am. I've had people complain that that is too early. So, if I schedule an email for California to receive it at 10am, I risk sending it at lunch time in the East or later. However, our best opens are in the morning. It would be great if the emails are sent based on recipient's time zones. I know this is difficult to do, but if there were a customer field for time zone, would it be possible to time the send based on that value?