Here we present useful links for winter biking.
Studded tires manufacturers
(in English and Finnish)
Finnish manufacturer which produces extremely light studded tires. Their products are very popular.
Schwalbe - Professional Bike Tires
German manufacturer which supplies Japan with studded tires at most.
Links for meteorology
Japan Meteorological Agency
(in Japanese and English)
-Modified Rainfall Radar Images
-Last Meteorological Data of Southwest Hokkaido
It is the most useful site for cycling in the snow.
Het Koninklijk Nederlands Meteorologisch Instituut
Its meteorological calculator is useful.