Hiking in long pants has always been a struggle for me. While the morning might start out cool enough to warrant long pants as soon as I start going uphill I’m generating enough body heat I just want to strip down to my shorts.
But then I get to the top of the climb, which is often exposed and/or windy, and I immediately want to put my long pants back on. Other times the air temp might not justify long pants but I want to protect myself from vegetation and bugs (overgrown trail, poison ivy, mosquitos) or intense direct sun (the desert or reflecting off of snowfields)… but once again, there is still the overheating issue.