I believe (but am not sure) that Fahrenheit summer and Fahrenheit 0 degrees are identical. Compared to the original, Fahrenheit 0 degrees is (as you would expect) lighter, fresher (in a way) and doesn't seem to last as long. besides that it is very very similar to the original. not as intense. Since Fahrenheit seems to work best in winter (wouldn't you agree?) Fahrenheit Summer is like Fahrenheit except if you wear it when it's hot out you don't feel overwhelmed with this heavy cloying fragrance. Hope this helps.