It's getting quite cold.
As I write this article on Wednesday, November 23rd, the temperature outside is 16°C. And it's raining.
It's about time to turn on the heating in the room and use the humidifier.
I get cold easily, so I often wear a down jacket in the winter, but I've always felt that it's difficult to regulate body temperature with heavy outerwear like a down jacket.
It's not a problem when I'm walking outside, but I often find myself taking off my outerwear and holding it in my hand, for example on the train or inside a store when shopping.
I know I shouldn't wear a down jacket in the first place, but since it's cold outside I still end up wearing one.
What I'm trying to say is that even if you don't wear a down jacket, you can stay warm enough by layering clothes in winter, and it's easy to regulate your body temperature, so you can stay comfortable anywhere.
However, this does not mean that you should just layer your clothes mindlessly.
By wearing a highly windproof outer layer over an inner layer such as fleece or knit, you can maintain your body warmth just as well as with heavy outer layers such as down!
Let me explain the reasoning a little.
Fleece and knitwear can trap plenty of warm air.
The idea is that by wearing highly windproof clothing such as a nylon outerwear, you can maintain warmth and prevent the warm air from escaping.
Just knitwear gives the impression of being warm, but wearing just one knitwear can actually be surprisingly cold...
Explaining why knitwear and fleece are able to trap warm air would take too long, so I will do that another time.
Of course, it is common to wear an outer layer over a sweatshirt, etc.
The fact is that it is difficult for the body to warm up.
To summarise the contents of this article:
Heavy outerwear like down jackets are great, but in Tokyo winters, a crinkly nylon outerwear layered over a knit or fleece inner layer is enough to keep you warm, she said. 
P.S.
Now I remember,
" Is it better to put a blanket on top of or under the duvet to keep warm? "
There was a similar story a few years ago.
In conclusion, it seems that it is warmer to put a blanket on top of a duvet.
If you're curious about the reason, check it out.
-End-
Written by Kuroda
Instagram : ju_kuroda