I don't think there's a bond between the early summer and the earthquakes.
The summer hasn't arrived early everywhere. We can't expect to have the same kind of summer or winter we had last year. One year, we have a cold winter and the other year we have a mild winter. It's a cycle. It may be due to the Global Warming, although I think we still can't feel the changes.
As for the earthquakes...well, they happen every now and then.