India is likely to receive ‘above normal’ monsoon rainfall, in 2025 as per the India Meteorological Department (IMD).
- This marks the second consecutive year of ‘above normal’ monsoon (2024 saw 8% more rainfall).
About Above Normal Monsoon
- An above-average monsoon refers to the southwest monsoon (June–September) bringing more rainfall than the long-period average (LPA), which is currently around 87 cm (or 870 mm) across India.
Reasons for the ‘above normal’ Monsoons
- Absence of El Nino: El Nino, which involves warming of the central equatorial Pacific, is typically linked to weaker monsoon rains in India (in 6 out of 10 years).
- Its absence in 2025 is contributing to the likelihood of surplus rains.
Long Period Average (LPA) of Rainfall
- It refers to the average annual rainfall over a long period of time, typically calculated over a 30-year period (WMO Recommended).
- It is used as a benchmark to assess rainfall trends and deviations in a given region.
- The LPA helps in understanding the variability of rainfall and in assessing whether a particular year’s rainfall is above or below average.
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- Below-Normal Eurasian Snow Cover: The Eurasian snow cover or the snow cover areas of northern hemisphere and Eurasia from January-March 2025. This snow cover was below normal.
- There is an inverse relationship: less snow usually leads to more monsoon rain.
- Neutral ENSO Conditions with La Nina-like Features: ENSO (El Nino–Southern Oscillation) is currently in a neutral phase. However, atmospheric circulation patterns resemble La Nina, which is typically favorable for the Indian monsoon.
- ENSO is a climate pattern involving temperature changes in the central and eastern Pacific Ocean.
- It has two phases: El Nino (warmer waters, weaker monsoon) and La Nina (cooler waters, stronger monsoon).
- Neutral Indian Ocean Dipole (IOD) Conditions: Currently, the IOD is neutral, and it is expected to remain so during the monsoon.
- IOD refers to see-sawing temperature differences in the Indian Ocean with a ‘positive’ IOD — linked to warmer sea-surface temperatures, generally linked to better rainfall.
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