We had a cool, wet summer here, I do have to say it adversely affected the flavor of the blackberries (Also delayed them by a couple of weeks, they are normally peaking for a week after the 4th but this year it was more like the third/fourth week of July.  Plump but watery and damn' near flavorless (They need bright sun for the sugar to form at ripening), fortunately I still have a couple of gallons frozen from last year. 
Damn you, Anthropogenic Global Warming, why must you make summers so cold and wet?!? 
