Does the weather have much of an influence on Black Beetle?

Yes absolutely.

A very cold wet winter will lower the number of adults surviving into spring.
A cold wet spring will lower the number of egg hatchings.
And of course a wet summer will allow our grasses to be able to develop more root than the larvae can eat.

So when choosing ryegrass cultivars in the good season never forget the fact that a good beetle breeding season could be just around the corner!