India’s southwest monsoon in 2025 delivered 108% of the long-period average (LPA) rainfall, almost identical to last year. Yet, a closer look reveals that excess rainfall was significantly more widespread across key kharif-growing regions, according to CRISIL’s latest Rainfall Distortion Index (RDI). The index measures the extent of excess or deficient rainfall in kharif-growing regions during the southwest monsoon season.
The Rainfall Distortion Index (RDI), which evaluates the spatial distribution and intensity of abnormal rainfall, stood at 18.7 in 2025, its highest positive value in 14 years. This compares with 17.9 in 2024 and a five-year average of 9.9, signalling that rains were in excess in the kharif crop-growing states (hence a positive reading) and that the excess rains were the most widespread in 14 years.
A higher RDI implies that rainfall not only exceeded the average but was also distributed unevenly, with more regions receiving excessive precipitation. The findings highlight a critical aspect of India’s monsoon dynamics, while total rainfall remains above normal, its uneven spread continues to pose significant risks to agricultural output.
An analysis of past RDI trends shows that both excess and deficient rains can hurt kharif output, with crop damage reported for rice, cotton, groundnut, maize, and horticulture crops. Rabi crops, which rely more on soil moisture and irrigation, have generally fared better in years of excess rain.
Kharif Crops at Risk, Rabi Prospects Bright
CRISIL’s analysis reveals excess rainfall throughout the season in 10 states that jointly account for 58% of India’s kharif-growing area. This is expected to affect kharif output in Punjab, Rajasthan, and Telangana, though the impact at the national level may remain limited.
As of mid-October, when the southwest monsoon withdrew, pan-India rainfall was 27% above the cumulative LPA, with excess to large excess rains in key crop-producing states such as Punjab (478% above LPA), Haryana (390%), Rajasthan (371%), Bihar (190%), Uttar Pradesh (90%), and Madhya Pradesh (32%).
India’s recent monsoon history shows repeated phases of above-normal rainfall, with 2019, 2020, 2022, 2024, and 2025 all recording excess rainfall at the all-India level. Rainfall remained above normal in all four monsoon months of 2025, distinguishing it from previous years. Of the top 20 kharif-growing states, 10 recorded excess rainfall, compared with five in 2024.
CRISIL’s analysis suggests that rabi output tends to perform above trend during years of surplus monsoon, as additional rainfall enhances soil moisture and reservoir levels, providing farmers with a stronger base for sowing wheat, mustard, and other winter crops.
Rabi prospects therefore appear bountiful, supported by healthy soil moisture and reservoir conditions. However, excess rains in key kharif-growing states and unusually high October rainfall could cause some crop damage.
Rainfall Distortion Index (RDI)
To calculate the RDI, state-wise rainfall data from the India Meteorological Department (IMD) — measured as percentage deviation from the LPA — is mapped against the area under kharif cultivation provided by the Department of Agriculture and Farmers Welfare.
The RDI is then computed as a weighted average rainfall deviation, where a state’s share in the all-India kharif area serves as its weight. Since the kharif area is used as the weight while computing the index, the RDI effectively indicates the vulnerability of kharif production to excess or deficient rainfall.
CRISIL’s RDI provides a critical lens into the impact of abnormal rains during the southwest monsoon season, one of the biggest risks to India’s agriculture and inflation.