Hi ~ I live an hour south of DC and go to Skydive Orange. It is a little farther south than Hartwood if you're in the DC metro, but is also a great place that flies a Super Otter with lots of jumping going on year round, weather permitting. Check out their website here: http://www.skydiveorange.com/
I think you would find the extra 30 minutes of driving worth it.
Blue Skies,
Julie