It's still cold out and your leather seats are feeling about as chapped as your hide because the dryness is sucking out all the oils that came with that piece of cow. You've discovered you can't raise temps by sheer willpower, but you can plan ahead so when the weather takes a turn.

Lube your leather with some treatment that will clean, soften and leave a subtle shine on your interior. Use a pH balance-neutral compound to replace lost oils in the leather fibers of seats that are over 30 years old so they stay plump and flexible.

Newer leathers have a micro thin polymer coating that won't allow oils to penetrate so Leather Lotion is used for cleaning and to prevent UV rays from drying out the topcoat and cracking it.

You've endlessly buffed the outside of your car, maybe the inside could use the same treatment?