London Heathrow Airport





Number of days available for climatic review

ParameterJanFebMarAprMayJun
Tmax123711501268122812601230
Tmin123911501270122812611228
Duration of sunshine000000
Precipitation186169190181186180
Humidity/Visibility185168184179185179


ParameterJulAugSepOctNovDec
Tmax126612701248129412571302
Tmin127012721249129512581300
Duration of sunshine000000
Precipitation185190214215210217
Humidity/Visibility184185206210208214


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.