Seven hours different and offset weekends
Saudi Arabia is seven hours ahead of me here in Kentucky. Korea was 13 hours ahead. Turns out, it’s actually harder for me to coordinate with Saudi Arabia than with Korea.
With Saudi, I can really only send one email per day. The next day, they’ll respond to my email. The day after that, I’ll get to respond to their email. And on it goes.
Of course, that assumes we’re each able to respond every day.
To throw another wrinkle into the interaction, Saudi Arabia runs on the Muslim week, so weekends are Thursday and Friday. Lots of fun.