I shot matches year-round up to two (2) Summers ago.  I now have a 90-degree Rule (if it's hotter than 90, I don't go to matches).  The main reason is that it simply is not comfortable (and I hate the sweat running off of my hatband, onto my forehead and then onto my shooting glasses).
But, even with this limitation, I shot 43 matches last year.  Basically June to September are out for me.  There is plenty of shooting to be done during the other 8 months.
Now, does this mean I don't shoot at all during the Summer months?  No, I do practice three (3) to four (4) times each week after 7:30 PM.  Am lucky that a fellow cowboy shooter has a range on his property less than 10 minutes away.  Shoot roughly 300-400 rounds in practice each time, about double each night of what we expend during an actual CAS Match.
I would love it if Matches started at 7:30 PM, but I don't think that is going to happen any time soon......then Summer shooting might be in the cards for me again.
Oh well, C'mon September..........!