The Indian monsoon, a lifeline for millions, arrived earlier than expected in 2025. Normally expected around June 1 in Kerala, this year’s Southwest Monsoon hit on May 26, marking a five-day early arrival. This shift has sparked widespread discussions among meteorologists and climatologists.

According to the India Meteorological Department (IMD), this unusual pattern is not an isolated event but part of a broader climatic change, influenced by oceanic temperatures, wind patterns, and global climate cycles.

What Caused the Early Monsoon in 2025?

Strong Madden-Julian Oscillation (MJO)

The Madden-Julian Oscillation (MJO), a large-scale atmospheric disturbance, is moving eastward over the Indian Ocean. It boosts convective activity and strengthens monsoon winds, hastening their advance over the Indian subcontinent.

• MJO phases bring heavy cloud formation and rainfall.
• It intensified the southwesterly winds earlier than expected this year.

Above-Normal Sea Surface Temperatures (SSTs)

Elevated sea surface temperatures in the Arabian Sea and Bay of Bengal have been observed in satellite data. Warmer oceans contribute to:

• Faster evaporation
• Increased moisture in the atmosphere
• Stronger and more sustained monsoon currents

Weaker Anti-Cyclonic Circulation Over Arabian Sea

Normally, an anti-cyclonic circulation near the Arabian Sea delays the monsoon onset. However:

• This system was significantly weakened in May 2025.
• Allowed moist winds to progress inland earlier than usual.

Climate Change-Induced Weather Variability

Climate experts point to global warming as a long-term contributor:

• Rising temperatures disturb monsoon onset and retreat.
• Leads to more frequent extreme rainfall events, erratic timelines, and flooding.

Timeline of Monsoon Onset in 2025

Kerala Receives First Monsoon Showers

• Official onset: May 26, 2025
• Five days earlier than the normal date (June 1)
  

Heavy Rains Lash Mumbai

• Red Alert issued by IMD for Mumbai and Konkan region on May 28
• Caused severe waterlogging, delays in transport, and flash floods

Impact of Early Monsoon

Positive Outcomes

• Boosts agricultural sowing for crops like rice, pulses, and millets.
• Eases water scarcity concerns in drought-prone areas.
• Strengthens reservoir levels before peak summer demand.

Negative Consequences

• Catches city administrations off-guard, leading to floods.
  Hampers pre-monsoon crop harvesting.
• Affects infrastructure projects and public transportation.

What Experts Say

“This year’s early monsoon is a wake-up call. While not unprecedented, it’s increasingly becoming common, highlighting how sensitive our monsoon systems are to small atmospheric changes.”
— Dr. Rajeevan M. Nair, former Secretary, Ministry of Earth Sciences

“Coastal cities like Mumbai must urgently revamp their drainage infrastructure. Early monsoon paired with high tides can paralyze the city in hours.”
— Sunita Narain, Director General, CSE

Looking Ahead – What to Expect in June-July 2025?

• The IMD has predicted a “normal monsoon” for 2025, despite its early arrival.
  
• Rainfall may remain intense across western coast, northeastern states, and central India in June.
  
• El Niño weakening is expected to support stable rainfall patterns, according to latest forecasts.
  

Final Thoughts

The early arrival of the monsoon in 2025 may have taken India by surprise, but it reflects larger shifts in global climate behavior. While it brings relief from scorching summer heat and supports agriculture, it also underscores the urgent need for urban and rural preparedness. From better drainage systems to adaptive cropping strategies, a long-term climate-resilient approach is no longer optional—it is essential.

By – Nikita