TL;DR: India’s 2025 southwest monsoon delivered 936.8 mm of rainfall, or 108% of the long-period average, with 80% of districts receiving adequate rainfall, the best district-level performance in over a decade. Yet the national average masks important patterns. June remains the most vulnerable month, including the current monsoon, if the current trend persists. August is highly unpredictable, and September is increasingly carrying the season. The monsoon is not necessarily weakening, but becoming more uneven in space and time. Looking only at the seasonal average misses much of the story.

Context

India receives roughly 75% of its annual rainfall in just four months. That explains why the southwest monsoon is more than a seasonal weather event. The 2025 monsoon offered rare, broad relief: rainfall reached 108% of the long-period average, with 936.8 mm recorded across the country, steady and well-distributed across all four months. Three subdivisions, Arunachal Pradesh, Assam & Meghalaya, and Bihar, remained the exception. For the rest of India, it was, by every measure, a good year.

The season begins, by convention, when the monsoon sets in over Kerala, normally on the 1st of June. In 2026, it arrived three days late (i.e. on 4^th June, 2026). This piece traces that uncertainty across time, examining how monsoon behaviour has evolved and what the data reveals about shifting patterns.

Who compiles this data?

The data on monsoon behaviour, such as onset dates, rainfall distribution, and seasonal anomalies, is documented each year by the India Meteorological Department in its annual monsoon report.

Where can I download clean & structured data related to this?

Clean, standardised datasets on year-wise, month-wise, and region-wise monsoon rainfall, including IMD subdivision-level actual rainfall data, are available for download on Dataful.

Key Insights

The 2026 Monsoon Has Not Started Well

Three weeks in, the country is 42% below normal rainfall for the June 1–23 period. Central India is the worst hit at -64% of normal, receiving just 39.5mm against an expected 110.2mm. East and Northeast India, which already underperforms year after year, sits at -40%. South Peninsula is at -26%, Northwest India at -19%. The monsoon set in over Kerala three days late.

80% of Districts Got Enough Rain in 2025, the best ever in a decade

In 2025, four out of every five districts in India received normal or above-normal rainfall during the southwest monsoon season, the strongest district-level performance in more than a decade of available data.

Nationally, 80% of districts recorded adequate or excess rainfall, the highest share observed between 2013 and 2025. Yet the headline figure masks an important reality: the remaining 20% or more than 140 districts still experienced rainfall deficits. They are the part of the monsoon story that national averages often obscure.

A decade earlier, the picture was markedly different. During the weak monsoon years of 2014 and 2015, nearly half of all districts recorded deficient rainfall. Since 2019, conditions have improved steadily, with the share of deficient districts remaining below 30% in most years. In 2025, that proportion fell to its lowest level in the available record.

The improvement is also evident at a broader regional scale. Of India’s 36 meteorological subdivisions, only three recorded deficient or large-deficient rainfall in 2025. Excluding 2019, which also saw just three deficient subdivisions, this is the lowest number since 2012, underscoring the unusually widespread distribution of monsoon rainfall across the country.

In 2018, Only 12 Districts Had Large Excess Rain. In 2025, It Was 67

The IMD classifies each district’s rainfall against its own long-period average. A district is “normal” if its rainfall falls within 19% above or below that baseline. “Excess” means 20–59% above, “large excess” means 60% or more above, and “deficient” and “large deficient” follow the same logic on the other side. Every district is measured against its own historical norm, not a national one. This is important since a district in Rajasthan receiving 300mm and one in Kerala receiving 3000mm can both be “normal” in the same season.

The single shift from 12 to 67 large excess districts in seven years captures something important about how India’s monsoon has behaved recently. It is not just that more rain is falling. It is falling in more places.

Across the nine years from 2017 to 2025, the combined count of large excess and excess districts has risen from 112 to 254. Normal rainfall districts have held relatively steady, between 289 and 327. The real movement has been at the extremes, with more districts receiving surplus rain and fewer receiving none worth counting.

June Struggles, September Delivers: That’s Been India’s Monsoon Pattern for a Decade

Across the 36 meteorological subdivisions tracked by the IMD, the monsoon does not behave the same way every month. One pattern stands out clearly: June is often the weakest month.

In 2019, as many as 28 subdivisions recorded deficient rainfall in June, while only one saw large excess rainfall. The deficient count stood at 20 in 2022, 14 in 2024 (including two large-deficient subdivisions), and 10 even in 2025, a year that was otherwise strong at the national level. More often than not, June is where the monsoon struggles first. It is also the month that matters most for kharif sowing, making early-season rainfall shortfalls particularly important.

The second pattern is September’s growing role in lifting the season. The number of subdivisions recording excess or large excess rainfall in September was nine in 2017. It rose to 23 in 2019, 20 in 2021 and 19 in 2025. Increasingly, a larger share of the season’s rainfall appears to be arriving towards the end of the monsoon. A strong September can refill reservoirs and improve national rainfall averages, but it cannot make up for a missed sowing window earlier in the season.

July is usually the stabilising month. The number of subdivisions receiving normal rainfall rises sharply, reaching 25 in 2018, 16 in 2016 and 18 in 2025. At the same time, the number of deficient subdivisions generally falls from June levels. In many years, July is when the monsoon settles into a more predictable pattern.

August, however, remains the wildcard. In 2019, 10 subdivisions recorded large excess rainfall. In contrast, 2021 saw no large excess subdivisions and three large-deficient ones. In 2023, there were again no large excess subdivisions, while 14 recorded large-deficient rainfall. In 2025, seven subdivisions received large excess rainfall, and none recorded large deficient rainfall. More than any other month, August continues to produce the widest swings in monsoon performance.

Why does it matter?

India’s southwest monsoon is more than a weather event; it underpins the country’s food, water and energy security. A good monsoon brings widespread benefits, while a weak one can have serious consequences for farmers, households and local economies.

It is also India’s largest unmanaged public good. Crop insurance payouts, drought declarations and reservoir planning are often tied to seasonal rainfall averages. Yet the data shows that the real impacts are felt much earlier, in specific districts and individual months, long before the season’s final numbers are known.

This suggests a need for policies that look beyond seasonal headlines and pay closer attention to monthly and district-level rainfall patterns, where the effects of monsoon success or failure are actually felt.

Key Numbers

• Districts with Deficient and Large deficient rainfall in SW Monsoon (%):

  2015: 49%; 2020: 25%; 2025: 20%

• Districts with Rainfall Quantity

  • Large Excess:  2017: 23; 2021: 59;  2025: 67

  • Large Deficient: 2017: 8; 2021: 17;  2025: 12

  • Normal: 2017: 313 ; 2021: 290 ;  2025: 327