LPA is the average rainfall received by the country as a whole during the south-west monsoon, for a 50-year period. The current LPA is 89 cm, based on the average rainfall over years 1951 and 2000. This acts as a benchmark against which the rainfall in any monsoon season is measured.
Categories: IMD maintains five rainfall distribution categories on an all-India scale which are –
Normal or Near Normal: When per cent departure of actual rainfall is +/-10% of LPA, that is, between 96-104% of LPA
Below normal: When departure of actual rainfall is less than 10% of LPA, that is 90-96% of LPA
Above normal: When actual rainfall is 104-110% of LPA
Deficient: When departure of actual rainfall is less than 90% of LPA
Excess: When departure of actual rainfall is more than 110% of LPA
