I started shooting Mfta winter courses a few years ago. One thing that was different (then) was they were 30 shot course.
On a freezing day, it was enjoyable to shoot 30 good targets.
Go back to Wafta the week after and on a Freezing day, 30 were enjoyable, the last 10 were lets get these done asap and get warm.
As such, we brought a rule into Wafta saying a club could in Winter (We run a summer league x40 shot series) put out a x30 shot course as apposed to a x40 shot course, should the conditions dictate it. I know I have done this once on a cold shoot at tondu.
I`d take 30 good enjoyable targets over 40 any "winters" day. Winter I judge as 6 degrees or lower.