If I was asked by prospective tourists from overseas which months it is good for them to visit Japan, I might answer them two months from December to January except New year holiday period(December 25 - January 7) are good. On those days, visitors can avoid crowds and there are many days when the sky is clear and blue on the Pacific Ocean side. In winter, in the Kanto area including Tokyo, it is cold but it is not so cold. The temperature goes up to 9-10 degrees Celsius. On the contrary, the Sea of Japan side often has a snowfall. In my case, every year I enjoy going on a trip around Japan from January to the early Febuary.  Shall we have a happy time in Japan in such a nice season ?