It will be interesting to see what kind of attendance there is for those games.
In the past two seasons the Nats' lowest attendances have come in April:
2012 - Wednesday 18th April vs Astros (14,520) - weather 53 and overcast
2011 - Tuesday 12th April vs Phillies (13,413) - weather 55 and overcast
[weather cites from ESPN.com match reports]