Well, I often do here in Michigan, and several times have had a much nicer fall crop than a spring crop. Should be even easier in your climate.

For me, right NOW is the ideal planting time -- around the 20th to 25th of July. My average first frost is October 11th, or about 2 1/2 months from now. Maybe you can extrapolate from that. Id' think because of your summer heat, you'd want to wait maybe about 2 more weeks, then your harvest would push into later October -- you generally have very nice, prolonged falls there from what I understand.