Check out the winter festivals
In Japan, festival fever dies down with the coming of winter, but it does not go away completely. Some of the country’s best festivals take place in the colder months, such as the annual Sapporo Snow Festival (Yuki Matsuri). During this festival, the city is filled with stunning sculptures of snow and ice and illuminated with festive lights and seasonal displays.
Experience an unusual tradition: Yonekawa Mizukaburi
This is the appearance of a Miyagi prefecture tradition called "Yonekawa Mizukaburi." Men in straw costumes with their faces heavily painted in black ink act as divine messengers as they prepare buckets of water and throw them on houses in the area in order to protect them from fire. During the winter in Japan around the New Year season, many unusual traditions from ancient times are still practiced. If you are interested you are by all means welcome to check it out, just be sure to thoroughly observe the safety precautions to prevent any interference.
Eat some Hokkaido Crab
Crab is one of the staple winter foods of Japan. Many kinds of crabs are in the winter, so make sure to try some. Hokkaido crabs are particularly tasty, and they are available throughout the country. Some fancy restaurants served them as well as chain restaurants so the prices can really vary. You can get some pretty good crab at a reasonable price at Kani Doraku.
Watch Sumo
Sumo competitions are held throughout the year but the ones held in January gather particular attention as they are the first in the year.
Enjoy winter sports in Niseko
Advertising displays and restaurant menus in Niseko are written in English because this town is popular among foreign people. Also the population of foreign people living there has been increasing.
Go to the Sapporo Snow Festival
This is the mother of all snow festivals in Japan. It attracts huge crowds of foreign and national tourists for good reasons. It has the some of the most impressive snow structures that you will ever see, the food in Sapporo is great, and there are three huge sites where you can enjoy different activities, and see different things. The illuminated snow and ice structures are the highlight of the festival so you can enjoy it well into the evening.
Admire the Plum Blossoms
Plum blossoms are not as popular as the sakura (cherry blossoms) but they are quite impressive too. They start blooming in mid-February in central Japan. One great place to see them is at the Sazuka Forest Garden in Mie Prefecture. If you are in Tokyo, Hanegi Park is the spot. It is located a 5-minute walk from the Umegaoka Station (Odakyu Line) or a 7-minute walk from the Higashimatsubara Station (Inogashira Line).
Watch monkeys enjoying themselves in hot springs in the snow
There are natural hot springs all around Japan, and there are many tourists that enjoy the open-air hot springs. Wildlife in the mountains also utilize them for medicinal purposes or just to keep warm.
The most famous hot springs where you can see monkeys enjoy the hot springs is Yaenkoen (wild monkey park) in Jigokudani (Hell's Valley) in Nagano prefecture. The park opened in 1964 and ever since then you could view monkeys in close proximity. Recently, there have been many videos of monkeys relaxing in the hot springs.