Cool, thanks. I was just thinking about this thread a couple days ago. My experience may be a little different than yours, but I suspect it's caused more by my getting many of the C. baccatums in the ground later than the C. chinense, after the heat wave had already set in. I got the C. annuums in last of all, in late June, and they are doing okay, but I believe that's because they are in the lowest part of the garden, where all the water flows to...
Next year I will plant out everything in the same 1-2 week period, in order to keep as many variables as I can constant...
It seems to me that hot weather vigor varies more between individual varieties of any given species of Capsicum than it does between the species themselves. In my garden Aji Limon and Guampinha de Veado are growing and producing exceptionally well in the Heat Wave of 2011, while Aji Amarillo always seems to droop in the middle of the day, and has yet to produce one pod. In the little C. annuum patch, the New Mexico chiles are struggling every day, while Thai Chile hardly seems to notice, and NuMex Jalmundo just keeps bushing out, reaching for the sky, and pushing out chunky, juicy peppers. As for C. chinense, everything I've got is growing and producing well through the heat and the drought, with the exception of Trinidad Scorpion, which, while growing quite tall (6 feet) and bushy, have produced a total of 10 small pods from 4 plants...
Probably the biggest lesson I've taken away from this summer's garden is, for my particular little plot, and it's true across all varieties and species: To ensure healthy, productive plants through the extreme midsummer heat, be ready at plant-out time with big, robust transplants, with large root balls and lush leaf canopies. And do the plant-out as early as possible, not so much as to be the "first guy with pods," but to ensure that the plants have as much time as they can get growing in the temperate weather, to establish even more roots and leaves to defend themselves against the oncoming hot and dry brutality of the Southern Summer....