Hey Koozemani, can give you some info for the southern end, New River Beach, Beaver Harbor & Deer Island. (All temps in Fahrenheit) July water temps are in the mid 40s, vis is anywhere from 5' to 20'. The sites I mentioned are all shore dives. Surge in July is not an issue. Currents at the first 2 sites are mild and are diveable during any tide.
Deer Island is quite another story, drift dives are possible before the low slack, and there is diving on the high and low slack. It is considered by many to be the best shore dive location in the maritimes.
(IT IS ALSO THE MOST DANGEROUS) Currents can be extreme, and unforgiving. But the marine life is abundant, and the vis is generally very good.
Do not do any of the dives there without a guide.
I can give you more info if you like.
Hope this helps.