Older and colder

OK, winter is approaching and this year starting in the Fall I have been feeling cold, indoors, every day, now starting at 4 PM.  That's when the sun starts to go down and, as evening approaches, temperatures start to drop. At 4 PM I am home, indoors. With the heat on. My upper body starts to feel cold, and I put on a sweatshirt. Sometimes a jacket. The room temp is the same, 77 degrees F, not cold, not too warm. I remain feeling cold until I go to sleep at 11 PM then, under the covers, I am "normal". 

This is the first year I have had this "older and colder" weirdness. During the day, morning and afternoon I am not cold intolerant, I only feel cold in my upper body starting in late afternoon.

I recently went to my doctor for a checkup, lab tests et al and nothing was found that would explain this "older and colder at 4 PM" thing. 

I did a google search but found nothing that fit or explained this issue. I have none of the diseases or vitamin deficiencies listed that cause this. So, as often happens, I have to try and diagnose myself. Here goes ...

I am old, er older. Apparently, as we age our skin gets thinner and our circulation slows down. Yes, I have always been sensitive to temperature (and humidity) but this is a whole new sensitivity level. Feeling cold starting at 4 PM? Every day? OK, maybe aging is what's causing me to feel older and colder. Normal aging. If that's the case, what do I do about it? I could buy a heavier sweatshirt. Or a heavy sweater. I could turn up the indoor temperature a bit, starting at 4 PM. I could take another hot shower every day at 4 PM, but that might dry out my skin even more. I don't have to move to a warmer climate, I already live in Southern California. 

Now that I better understand what is likely happening to me, and why, I will consider my options regarding how best to deal with being older and colder and how best to restore my feeling warm and fuzzy at night during winter.