"During the last 25 years, long range seasonal monsoon rainfall forecasts of the government for the country as a whole were found to be accurate in 12 years or 48 per cent," he told the Lok Sabha in a written reply.
Reddy said the India Meteorological Department had issued partially correct forecasts, within an error bar of eight per cent, for five years or 20 per cent cases in the 25 year period under evaluation.
"Therefore, monsoon forecasts have been either accurate or partially correct in 17 years or 68 per cent of cases," he said.
On short-range forecasts issued three days in advance, Reddy said the accuracy was in the range of 70 to 95 per cent.
The skill of district level rainfall is 75-85 per cent in monsoon season and more than 85 per cent in non-monsoon seasons, he said.
"By duly considering the difficulties involved in monsoon prediction, the above success rate may be considered as very encouraging," Reddy said.