We've had a strange event this summer - it's called an "updwelling" and brings the cold ocean water from the depths up to the surface. Some days the ocean temp here has been 65 degrees! Brrr! Nothing like the usual summer warmth -this has even been a problem with newly hatched sea turtles, they don't want to go in the cold water, so the beach patrol has had to round them up by the hundreds and take them way out to sea to release them (which they don't like to do BTW, because it doesn't "imprint" the baby turtles where to return to lay their eggs).
Anyway, even with the cold water, the beach has been busy, with lots of brave swimmers, so I bet your kids will still enjoy!