Niigata and Gunma adjoin, but their climates are very different in winter. It often snows here and there in Niigata. But in Gunma it hardly snows. It is reason the moist wind blowing from Nihonkai makes it snow at Niigata. After making it snow, the wind dry and blows into Gunma over the mountains. It is such dry and strong wind that it does not snow in Gunma.