18 1 国土・気象maritime meteorological observations, and aeronautical meteorological observations. This chapter provides information on temperature and relative humidity based on the "Past Meteorological Data," which summarizes the results of one year of ground meteorological observations conducted by national meteorological offices. The climatological normals in the meteorological statistics are supposed to use the cumulative average of consecutive 30 years counting from the year when the 1st digit of the year is 1 of Gregorian calendar internationally. They are used for 10 years following the statistics period and updated every 10 years. The current climatological normals in use are "The climatological normals of the year 2020",version 5 that are calculated based on the materials of the 30-years period from 1991 to 2020, and have been used since 21 May, 2025. See the Glossary for Terms in this chapter.
元のページ ../index.html#53