You can wait a week or so if you want, but it's not necessary. 2 yr old sod should be fine to aerate. If you can grab the sod and it stays put without ripping up easily, you're good to go.
"the Constitution is a charter of negative liberties" Barack Hussein Obama
If you like the job Granholm is doing for Michigan, you'll love the job Obama will do for the U.S.
“The best argument against democracy is a five minute conversation with the average voter.” Winston Churchill