Rain Revision: IMD To Change 80-Year-Old Monsoon Timetable

New Delhi: The India Meteorological Department (IMD) is set to change the 80-year-old schedule for the onset and withdrawal of southwest monsoon in the country.

The new ‘monsoon timetable’ to be used for this year’s forecast is expected to see nearly a 15-day change.

Why Change?

The revision of the monsoon schedule, which has been flowed since 1941, was necessitated by the delayed onset and withdrawal recorded across various regions of the country in the past few years.

However, the date of onset of monsoon over Kerala is expected to remain June 1, the Ministry of Earth Sciences secretary, M Rajeevan, said.

“The monsoon schedule was set long time back around the First World War. Though it was revised many times, IMD never effected them. We cannot use climatology of the 1940s to inform people of today,” Rajeevam said.

Erratic Pattern

According to IMD, the normal onset of monsoon begins on June 1 and withdrawal occurs by September 1.

However, 2019 saw the most delayed monsoon withdrawal on December 9, matching the pattern registered between 2014 and 2018.

“There are very few places in the country where the onset is early, but the withdrawal has been erratic with 10 to 15 days delay in some regions. The monsoon is delayed in central India while retreating late for northwest regions. This necessitated the change in schedule.” a report in Indian Express quoted Rajeevan, as saying.

However, no change is expected in the four-month duration of the southwest monsoon, he added.

Possible Impact

On the possible effect of the change in monsoon schedule, the secretary said it will have an impact on agricultural practices and farmers would need to change their traditional crop sowing period.

He said there are various reasons behind the change in monsoon pattern. Maybe, it is a systematic change and cannot be immediately attributed to climate change, he said, adding, “Monsoon has a large cycle of 60 years. If we take 30-40 years, the change could be due to that cycle.”