How is the email time zone determined?

When you schedule an email and pick a time to send, we determine the time zone according to the time that is set on your computer.

If you're a globe-trotter who starts their day in San Francisco, but ends the day in Zimbabwe, then you might want to keep this in mind when you're scheduling emails.

You can't manually adjust the time zone to San Francisco time if you're sending it from Zimbabwe, so you'll have to schedule the email according to Zimbabwe time, and make the appropriate calculations, so that your San Francisco recipients get your email at the intended time. This is a handy site to help you figure out the correct times around the world - http://24timezones.com/