Always a hard decision especially here in New England as the weather has no rhyme or reason!
Just looking at the accuweather.com projected weather forcast... (not sure how they can predict that far out when they can't typically get tomorrow's weather right but...)
http://www.accuweather.com/en/us/lac...016&view=table They're calling for cold nights still... Look at April 4 low of 21 degrees... I personally think it's still a bit early but it all depends on the individual system .Some are less exposed and can withstand a cold snap better than others...I know my system tends to be less resistant to freezing.