Southwest monsoon over Kerala before time this year, likely on May 26: IMD

📌 Summary:

• India Meteorological Department (IMD) Friday forecast that the Southwest monsoon will set in over Kerala on May 26 (with a model error of ± 4 days), against the normal onset date of June 1

• This will be the third consecutive year of early onset over Kerala — 2025 onset was May 27, 2024 was May 31

• The monsoon first reaches the south Andaman Sea, the Andaman & Nicobar Islands and the south Bay of Bengal around May 22; IMD said onset over this region is expected in the next 24 hours

• Crucial significance: India receives over 70% of its annual rainfall during the four-month June–September monsoon season — central to kharif sowing (paddy, pulses, oilseeds, cotton), reservoir refilling for rabi irrigation, hydro power, and groundwater recharge

• Onset timing affects sowing windows; an early but well-distributed monsoon supports kharif planting, while an early arrival followed by long dry spells can hurt yields

🎯 UPSC Relevance: GS1 — Indian climatology and monsoon dynamics; GS3 — agriculture, food security, hydrology, climate change impacts on rainfall variability.

📝 Prelims Facts:

• Normal onset over Kerala: June 1; monsoon first appears over south Andaman Sea ~May 22; full coverage by ~July 8
• "Monsoon onset over Kerala" criteria: 60% of 14 IMD-designated stations report ≥2.5 mm rainfall on 2 consecutive days after May 10, plus wind and OLR (outgoing longwave radiation) thresholds
• IMD is under Ministry of Earth Sciences (MoES); headquarters New Delhi; established 1875

🔑 Key Term: Southwest Monsoon — seasonal wind reversal from the Indian Ocean towards the Asian landmass driven by differential heating between land and sea; supplies the bulk of India's annual rainfall.