Normal rainfall in 111 of 155 monsoon years since 1871, 27 years were droughts

Looking at nearly 150 years of the country's monsoon history, rainfall has been normal in most years, long-term data from the IITM and the IMD show. Years of poor rain have not been the only ones to stand out; many years have seen a normal monsoon.

An analysis of rainfall from 1871 to 2026 shows that 111 years had normal rain. Twenty-seven years were droughts and 18 years saw above-average rainfall. However, Dinesh Mishra, a retired meteorologist of the India Meteorological Department, said El Nino is likely to strengthen through December this year, so a drought could develop.

To understand the monsoon trend from the long-term rainfall graph, looking at the average alone is not enough. In the graph's classification, years with rainfall more than 10 per cent below the average are treated as droughts. Years with rainfall more than 10 per cent above the average are placed in the wet category. All other years are counted as normal.

Normal rainfall does not mean a year was free of drought. El Nino is linked to a weak monsoon, but not every El Nino year has a drought. On the other hand, even when total seasonal rainfall is normal, its uneven distribution, long gaps between spells and heavy downpours in a short time can affect farming, water supply and arrangements in cities. Even so, the figure of 111 normal years is reassuring.

Mishra said, "This figure is for the whole country, but it applies to Maharashtra too. Earlier, the yardsticks for drought were different. Now, through the study of El Nino, La Nina and the IOD, changes in the weather can be understood more broadly. El Nino comes every third year and sometimes every fourth year. So a drought occurs in three to four years. This is why normal monsoon years are more numerous in the long-term data."