EnvironmentTuesday, 2 June 2026·The Hindu - Environment
IMD’s June 2026 Kerala monsoon forecast and onset criteria for TNPSC
IMD said on June 1, 2026 that the southwest monsoon is likely to reach Kerala around June 4, after revising its earlier May 26 forecast.
Key highlights
Direct fact
On June 1, 2026, the India Meteorological Department (IMD) said the southwest monsoon was likely to set in over Kerala around June 4, after earlier forecasting May 26 on May 15, 2026.
Key specifics
- IMD’s earlier forecast on May 15, 2026 was for Kerala onset on May 26, with a ±4-day model error window.
- A June 4 onset would be beyond the upper bound of that window, May 30, according to IMD’s own forecast range.
- IMD’s operational onset forecasts were accurate every year from 2005 to 2025 except the 2015 lapse.
- Onset over Kerala is declared only after 60% of 14 stations, including Thiruvananthapuram, Kochi, Kozhikode and Mangaluru, record 2.5 mm rain for 2 consecutive days.
- Two other conditions are required: westerly winds up to about 600 hPa and outgoing longwave radiation below 200 W/m².
Exam lens
Question type: Environment and geography fact match. Key facts: IMD, June 1 2026 forecast, Kerala onset around June 4, 14 stations, 2.5 mm for 2 days, 600 hPa, 200 W/m². TNPSC may ask the official onset criteria for the southwest monsoon over Kerala.