India Set for Earliest Monsoon Onset Since 2009: IMD Forecasts Above-Average Rainfall and Early Arrival in Kerala by May 27

Southwest monsoon begins early in Nicobar Islands; may bring 105% of normal rainfall, boosting hopes for agriculture, water reserves, and power generation

The southwest monsoon, a vital force behind India’s agriculture and water supply, has made an early entry into the Nicobar Islands, officially kicking off the 2025 monsoon season. The Indian Meteorological Department (IMD) expects the monsoon to hit Kerala by 27 May, marking the earliest onset since 2009—four days ahead of the typical 1 June date.

Fast-Paced Monsoon Progress

According to IMD, monsoon winds have already reached the southern Andaman Sea, eastern Bay of Bengal, and Nicobar Islands—a week earlier than usual. By 15–16 May, the system is expected to cover Sri Lanka, the southern Bay of Bengal, and the rest of the Andaman Islands. It will then begin its journey across mainland India via the southern Arabian Sea.

Monsoon Timeline Across India

The IMD has laid out a tentative schedule for the monsoon’s advance:

• 15 May: Andaman and Nicobar Islands
• 1 June: Kerala, Tamil Nadu, Lakshadweep, Assam, Meghalaya
• 5 June: Goa, Coastal Andhra Pradesh, Karnataka, West Bengal
• 6 June: Maharashtra (excluding some Andhra districts)
• 10 June: Mumbai, Central Maharashtra, Telangana, Chhattisgarh, Odisha, Jharkhand, Bihar
• 15 June: Gujarat, Madhya Pradesh, Uttar Pradesh
• 20–30 June: Rajasthan, Delhi, Haryana, Uttarakhand

Rainfall Outlook: Better Than Average?

The early onset isn’t just about timing—the monsoon is also projected to bring above-average rainfall. IMD forecasts suggest India could receive 105% of the long-period average, which stands at 87 cm. The limited influence of the El Niño weather pattern is a hopeful sign for a robust rainy season.

M. Ravichandran, Secretary of the Ministry of Earth Sciences, highlighted the potential for a strong four-month season—key for agriculture, reservoir storage, and hydroelectric generation.

Kerala’s Monsoon Onset in Recent Years

To put this year’s early forecast into perspective:

• 2024: 30 May
• 2023: 8 June
• 2022: 29 May
• 2021: 3 June
• 2020: 1 June
• 2009: 23 May

If the monsoon reaches Kerala by 27 May, 2025 will be among the earliest starts in nearly two decades.

Pre-Monsoon Showers Likely

Even before the monsoon’s full arrival, many regions—especially Maharashtra, Madhya Pradesh, Chhattisgarh, Andhra Pradesh, Telangana, West Bengal, and Tamil Nadu—could experience pre-monsoon showers and thunderstorms. Maharashtra may see stormy weather by 14 May.

Maharashtra’s Monsoon Outlook

The monsoon is expected to reach Maharashtra between 4 and 6 June, ahead of the usual schedule. If Kerala sees an early onset, Maharashtra may receive rainfall by 7 June, which would be a slight advancement.

Early Monsoon ≠ Uniform Rainfall

While the early arrival is promising, experts caution that it doesn’t guarantee widespread above-average rain. Monsoon patterns are influenced by a complex interplay of oceanic and atmospheric factors.

Why the Monsoon Is Crucial

With 42% of India’s population relying on agriculture and the sector contributing 18% to GDP, the monsoon is pivotal. It supports drinking water supply, irrigation systems, and power generation.

IMD’s rainfall classification:

• 96–104%: Normal
• 90–95%: Below normal
• Below 90%: Deficient

This year’s forecast of over 100% points to a potentially strong season, which could benefit both farmers and the broader economy.