I got married winter break of 3L year. I think this was the best time because school is not that big of a deal anymore, and you are not worried about studying for the bar. Also, if you are concerned about having your law license/ law degree in your married name, this gives you time to still get it done without being charged a fee. In my case, in Texas, all of the paperwork for this was due on February 1 (both for my school and for the State Bar). I got married at the beginning of January.
Congratulations and good luck deciding a time!