Athough I'm not in an extremely hot weather enviroment, the 180 degree t-stat helped lower the temp not only in the other seasons, but the summer as well. It does get decently hot at times here and my car now operates one letter lower in the temp gauge all year around. I don't have the fan mod or chip upgrade either, which I'm sure would help even more. So in my case the earlier opening of the t-stat helps keep the engine cooler. I also keep the antifreeze fresh by changing every 2 years. BTW, I used the Ford 180 t-stat from the lightning. Fit and operationally works great.