27 degrees here, but will warm up.-----Leather is not warm period, but blocks wind.
Suggest for your short rides-----get wide windshield, then any proper fitting rain jacket with quality feather jacket under works---I have tried all kinds of underwear and those advertised as magic---plain Hanes tee shirt next to skin works, followed by sweatshirt/flannel shirt.....and you stay warm/not cramped/ and dry----non breathing rain jacket seems to make no difference for up to 8 hours riding (condensation)----most bike gear sold in US market designed for crashing, not the practical part of cold weather riding.
My feather jacket is aging out----have to think of replacement, remembering feathers ain't warm when they are wet---there are materials that work when they are wet.