I had a plant in a black 3(?) gallon container that wound up sitting on a slab of concrete out back(full sun) last Spring.
I planted it for flavor, wanting a little bite but nothing overwhelming.
It was drought conditions here, and relatively hot and sunny. Although I tried to water it daily, I often got behind and noticed it drooping badly.
The first few peppers were what I wanted but they quickly crossed the line.
They got so hot that even cutting them up made my fingers tingle/burn.
I have another planted in the same pot now, same seed packet, grabbed a couple for a pizza a couple nights ago and they were still very mild. It seems to be on its second spurt of blooms and I expect them to be a little more flavorful.
So, I also suspect the dry(and/or hot) weather does indeed make them hotter. So "maybe" more regular watering would cool them down?
I'm speaking from very very limited experience though. I'm a recent transplant to Vero Beach, Florida and am trying to grow a few vegetables on a small, limited space basis.
And I do mean "try", I wasn't a gardener in Ohio, and I'm definitely not here either. I'll probably be posting a few pics of diseased tomatoes as proof... later.