el nino had a major part of this year's weather. winds also play a major part. precipiation is just by luck. If there's a cold front coming through and south nj and oc md are both forecasted for scattered storms and oc md gets the storms 3/4 times and south nj gets them 1/4 times, that's just plain luck. precipitation in the summer time is not very consistant.
The Bermuda High was set up for most of July and drove Mid-Atlantic weather. Hard to account for local differences other than the ebb and flow of where rain and thunderstorms pop up to cool things off. Don't ask me to explain how it works http://www.accuweather.com/video/972...?channel=bilok