I heard there are 7 weeks for flying ops. And flying Always starts slow and will intensify during those weeks. I was there in 2016 in 2nd week of April (so 5th week of course) and they flew great (log could be found on this forum).
Will be there myself between April 15th and 27th for some days as well. Be advised they do fly during weekends as well, we had 40 sorties on the saturday and few on the sunday.