In last week's post about the Archives, Jean W. asked the very good question:
Any chance there's a day of the week or a time of day when the student tours aren't there?
Unfortunately, the question is better than the answer. I have noticed a few broad trends over the last few years of doing this and I'm happy to pass them on, but I must caution everyone that I am painting with a wide brush. Besides the normal vagaries of visitor traffic, all of the following can be completely blown out of the water by the arrival of the dreaded "four bus group". I'm not sure why some groups of multiple buses insist on staying together and lumbering around town like a wounded brontosaurus, but they do. And like said dinosaur, they can crush your carefully planned out itinerary not from malevolence, but simple inattention.
That being said, here are some very general guidelines:
1. I very rarely have a school group booked on Monday. Most groups will come mid-week.
2. I used to try to get there when it opened at ten. It's not a bad strategy as this line moves faster than normal since there is no backlog inside. However, there's almost always a line waiting outside so it generally negates any advantage.
3. Traditionally, the Archives and the Holocaust Museum were the only thing open past 5, so it had long lines from 5-7. Now the Smithsonian's will be open later, so this might help to draw some of the crowds off. This is the first season the Smithsonian will be regularly open late, so that might help the evening lines. Keep your fingers crossed.
4. Most groups are at lunch from 12:30 to 2. I often get lucky then. As a corollary, this is a bad time to go to the Reagan Building or the Old Post Office.
5. School groups are marginally less likely to stay over the weekend. However, any drop off in school groups on the weekends is usually compensated for with more families and individuals visiting.
I hope this helps, and if any other guides or seasoned travelers have advice, please leave them in the comments.