World

Asia

Tokyo





Number of days available for climatic review

ParameterJanFebMarAprMayJun
Tmax155140155150155150
Tmin154140153150154150
Duration of sunshine155141155150217150
Precipitation155141157152155150
Humidity/Visibility154139153148153149


ParameterJulAugSepOctNovDec
Tmax155156179182177186
Tmin151155178180179185
Duration of sunshine186155180155150155
Precipitation156159181183180186
Humidity/Visibility152154176179176185


Climate data is usually derived from meteorological data of a certain number of years. The actual number of recorded years may vary from only a couple to 50 years or more. The quality of climate data depends on the number of available recorded years. Fewer years means less reliable data. The standart-period for reliable climate data is 30 years. For example, the mean monthly temperature for, let's say January, would ideally calculated from a total number of 930 recorded January-days. However, the usual number of recorded days is much smaller. The table above shows the actual number of recorded days for every parameter measured.