Dec 09 to Jun 12 was quite the stretch around here: the pre-Xmas 09 snow, the 10 Days that Whited Out Our World in late Jan/early Feb 10, Carmageddon, the tail end of Superoutbreak 2 in April 11, the quake, Irene, Lee, the derecho. Every one of them a big memory (Lee only because I happened to be driving though it) for most DMVers.
Since then: well, Jan 2016 of course. But other than than, a few isolated severe events (but anything region-wide?), a couple of good winters without a real signature event, the March 2018 windstorm (didn't really excite me, but I guess I'm the minority there). Nothing to make a scrapbook over. This summer's severe has been good for a lot of folks but all the real fun has edged me by. Then the B-listers: Isaias, the January 2019 snowstorm, a few localized (if notable) flash floods.
Just a personal observation, YMWOV. I realize you could lift a lot of 2.5 year periods at random throughout the 100+ year recorded weather of the DMV and make a similar conclusion, and the subjectivity with such an exercise is off in the nth dimension, but it'd be hard to beat 12/09-6/12 from my POV.