June 2026 set to be fifth driest-ever since 1901; monsoon advance over north delayed to early July

📌 Summary:

• With a 43%+ rainfall deficit, June 2026 is set to be the fifth driest-ever since 1901; India recorded only 85.2 mm against the long-period average of 165.3 mm
• June rainfall has been below 100 mm only four times since 1901 (1905, 1926, 2009, 2014); the driest was 2009 (87.5 mm)
• The large deficit may force a reassessment of IMD's seasonal forecast (it had predicted 92% for June, 90% for the four-month season); El Nino is strengthening but yet to peak
• Three of the four sub-100 mm June years (1926, 2009, 2014) were El Nino years; but in 1926 the season still ended 11% above normal, showing June deficits need not doom the season
• Causes of subdued June rain: weak monsoonal winds; stalled progress June 8-15 (onset over Kerala on June 4); unfavourable Madden-Julian Oscillation (MJO) phase; dry northerly winds dominating
• Crucially, late-May/June saw NO low-pressure systems or cyclones in the North Indian Ocean — unlike recent years (Remal 2024, Mocha & Biparjoy 2023, Asani 2022, Tauktae 2021) — depriving the monsoon of moisture and momentum
• Monsoon advance over Delhi and north India now expected in early July

🎯 UPSC Relevance: GS1 (Geography) — Indian monsoon mechanism, ENSO/El Nino teleconnections, MJO, and the role of pre-monsoon cyclonic activity; GS3 linkage to agriculture, food inflation and water security.

📝 Prelims Facts:

• Long-period average (LPA) for June rainfall = 165.3 mm; for the country, IMD defines "normal" monsoon as 96-104% of LPA
• MJO = Madden-Julian Oscillation, an eastward-moving band of rain-bearing clouds near the equator
• Driest June on record: 2009 (87.5 mm)
• Recent pre-monsoon cyclones: Remal (2024), Mocha/Biparjoy (2023), Asani (2022), Tauktae (2021)

🔑 Key Term: Madden-Julian Oscillation (MJO) — a recurring 30-60 day eastward-propagating disturbance of tropical convection that modulates monsoon active/break phases.