Forty year's seems pretty young.
On the other hand that's a lot of data, too.
The above table shows monthly rainfall for the history of Big Cypress Nat'l Preserve, from 1974 to 2014. The wet season (color coded blue) and dry season (color coded red) really jump out. As for the wettest month on record? Our wettest wet season month on record was June of 2005 (20 inches.) and our wettest dry season month was November of 1998 (9.2 inches.) As for the driest month that's a multi-way tie at zero.
The last time we had one of those was February 2004.