I dunno. Response to heat & humidity is relative.
I've owned around 25 cars, 2 of which have had A/C (including
my new winter beater 2007 Civic). I'll turn it on a few times to make sure it works.
But other people I know would wilt in the 3 or 4 weeks of "hot" weather we get each summer.
For those weeks, I put the beaded seat covers in the Firefly, and that's good enough.
I'm sure the Micra's A/C is awesome enough to reverse global warming with the windows left open.