I have a confession to make - I wore a pair of tights last week (it wasn't even that cold!).
However it was due to all other kit having been in the wash due to just normal dirt, or because of the total hammer ing it took through the thigh deep cow-poo/mud/water on my off-road run.
I felt so ashamed of myself I resurrected some really old kit, assigned to the scrap heap, but not actually thrown away, for my subsequent runs until other kit was washed. So normal service of short shorts all eyar has been resumed.
I don't know what it is, but I just hate running with stuff on my legs! My legs never seem to feel the cold, even in knee high snow, but I've got to wear gloves even when it's only mild out.