When do the leaves change colors in D.C.?

It depends on what the weather has been like - but the leaves should be beginning to turn at this time. Even if the colors haven't changed completely, there will be some that have and that still would be great to see. If you're flying there you should be able to see some foliage when the plane begins decent and maybe even before that - again depends on the weather. Have a great time and enjoy! :)

The color change is starting now. You won't see the peak next week, but you should see some color, esp. since the nighttime temps are now in the high 30's, at least for a couple of days. If you have time, you could rent a car and drive to West Virginia or Skyline Drive. Higher elevation = more color.

The leaves are *just* starting to change here - it's been slow because we got a warm spell at the beginning of October. So you might see some. If you get the chance to ride out into the mountains, that's where you'll see the prettiest color. Actually, if you want to see spectacular East Coast autumn leaves, you need to go to Vermont or Massachusetts or somewhere in New England. It makes DC's, or anywhere else's, seem positively mellow.