Believe it was also the case before that Doug but not entirely sure as my sense of time is bad.
But to compare some seasons, I looked back at the Monza for the league I'm in as I recently noticed a wet race in an earlier season was much faster than the normal dry seasons.
Season 27 - 11 Feb 2015 - dry -
36:43.825
Season 28 - 22 Mar 2015 - dry -
36:45.472
Season 29 - 01 May 2015 -
wet -
36:09.095
Season 30 - 10 Jun 2015 - dry -
37:14.281
Season 31 - 19 Jul 2015 - dry -
37:19.565
Season 32 - 30 Aug 2015 - dry -
37:15.532
Season 33 - 09 Oct 2015 - dry -
36:50.742
Season 34 - 11 Nov 2015 - dry -
36:49.882