What time is the traffic bad from Marin to SF on Sundays?

i just checked 511.org, which shows it's already begun (real-time info) now at 4pm -- anyone know a website with which you can look/plan ahead? with typical congestion patterns over the week?

4:30 on any day is horrible. It’s the weekend, so people are definitely coming from Mill Valley (muir woods, stinson beach) back to the city, so I’d say try and not hit that in the late afternoon.