After a drought, the rainy season comes about. Socially this is also true, in the sense that, after the drought, it's raining bitches n ho's. This season does not follow any particular pattern or mirror typical weather tendencies. It is completely random.

When you eat dirt for the first time and leave your family to build a shack in the woods

In Ireland, the months June, July and august. Normally the warmest months, they are also usually by far the wettest. The phrase illustrates that the Irish have long given up on their "summers".