Most people who don’t ride a bike on weekdays complain about car traffic. Yes, it’s bad everywhere, but if you leave early, or late, you can avoid the rush hour.
I leave between 7:00 and 7:15. I’ve noticed that there’s a lot more traffic at 7:15 than at 7:00. This avoids the rush hour, which generally runs from 7:30 – 9:30.
You can leave around 9:45 or later, to avoid traffic, if you like to work late.
Leaving early brings huge advantages. You ride when it’s cool, the bathrooms at work will be empty, there won’t be as much wind, you get off earlier when there won’t be as much traffic on the return trip, and it won’t be dark in the winter on the ride home. Of course, if you live in Alaska, you’re out of luck.
The worst time for early riding is before daylight saving time, when it’s dark in the morning at 7 a.m.