If you're dayhiking in August then I think a jacket will be enough. Overnight then you'll need more gear. Regarding pants, I think that depending on the person and their age. When I was in my 30's, I was fine in shorts all the way down to freezing temp. But as I get older my legs get colder a lot more easily. So at my age, I'll bring along all the gear even in August, but 20 years ago...probably leave the leg warmers at home.
