In January, it is still cold in Japan. It's unthinkable, being in Florida, that the weather would ever drop to 40F for more than a day or two in the year! But in Japan, it is firmly Winter weather, with the promise of Spring on the way! This week it has been in the 40s-50s (Fahrenheit) in Tokyo, and it is expected to be just as cold next week, if not cooler. Two layers of kimono is a likely scenario, or perhaps just thicker, warmer clothes!
This is a great opportunity for hime style: add cute hand-knitted gloves, some thick stockings with interesting patterns, boots, and hike the kimono up a bit to show them off. Make sure it all coordinates! Then add a haori and maybe a hat or scarf to the mix, and you're good to go in the chilly outdoor air.
As for me, I'd probably wear two thinner kimono layered on top of one another in indigo and tan, my mothers khaki leather insulated gloves, and some long leggings with usual zori and tabi. Once I adjust to the cold, I tend to like weather in the 50s, and can wear short sleeves in it. After a week of such temperatures, it's too 'hot' to wear much else!