Northeast’s Rainfall Pattern Turning Extreme, Finds 52-Year Climate Study
Northeast India is witnessing a striking shift in its monsoon pattern, with heavier one-day rainfall occurring alongside more frequent and longer dry spells, according to a 52-year climate study covering 1971 to 2022.
The study, titled ‘Evolution of Climate Extremes Over the Indian Subcontinent Using a Revised CEI’, analysed weather observations across India using data from the India Meteorological Department (IMD). The research was conducted by scientists from the IMD and the National Centre for Medium Range Weather Forecasting (NCMRWF) and published in the peer-reviewed International Journal of Climatology.
According to the study, Northeast India is the only region in the country showing a clear, statistically significant increase in extreme one-day rainfall.
The finding covers the entire Northeast region, including Assam, Meghalaya, Nagaland, Manipur, Mizoram, Tripura, Arunachal Pradesh and Sikkim.
Researchers attribute the rise in intense rainfall partly to a warming Bay of Bengal, increased atmospheric moisture and the complex terrain of the Northeast.
At the same time, the region is experiencing more frequent dry spells and increasing drought conditions.
Rather than indicating that the Northeast is simply becoming wetter or drier, the researchers interpret the combination of intense rainfall and prolonged dry periods as a sign of increasing monsoon variability or instability.
The study combined seven climate hazards including daytime heat, humid heat, heatwave severity and drought—into a revised India Climate Extremes Index (CEI). Trends were assessed using the Mann-Kendall statistical method.
Co-author M. Rajeevan said the Northeast is “swinging between extremes”, with heavier single day downpours occurring alongside longer dry spells. According to him, the changing pattern highlights the need for both flood preparedness and drought planning.
Lead author Thota Mohan similarly noted that the Northeast stands apart from the broader heat-and-drought pattern seen across much of the country, with the region showing a simultaneous rise in short, intense rainfall events and longer dry spells.
The findings underline the need for stronger rainfall-variability management, flood preparedness and drought-resilience planning across Northeast India.
