you should cover your knees when temp is 'in the 50 degrees'. so yes below 60, should cover
it up.
no matter who says what, do it.
this will ensure your legs and nerve endings will last as long as you do, whet
you get old. if you try to cheat (like I see a lot of idiots running shorts in the 40's
and even 30's) those people will get deep vein thrombosis and other nasty leg
problems when they get old.
cover them early and cover them often