An elderly woman walking during a heavy monsoon downpour on June 4, 2026. The IMD said conditions were “favourable for further advance of southwest monsoon into some more parts of central Arabian Sea, entire Goa, some parts of Maharashtra and Andhra Pradesh, some more parts of Karnataka, remaining parts of Tamil Nadu” and much of the Bay of Bengal “during next two to three days.”
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The southwest monsoon set in over Kerala on Thursday (June 4, 2026), the India Meteorological Department announced. This is three days later than the normal onset date of June 1, and five days behind the date the department had forecast.
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On May 15, 2026, the IMD forecast that the monsoon would arrive over Kerala on May 26, 2026, with a model error of plus or minus four days. The actual onset on June 4 overshot even the upper bound of that window, May 30, 2026, by five days.
It is the first time since 2015 that the department has missed its onset call beyond the error margin; its operational forecasts had been accurate every year from 2005 to 2025 save that one lapse.
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Having reached the coast, the monsoon is expected to gather pace. The IMD said conditions were “favourable for further advance of southwest monsoon into some more parts of central Arabian Sea, entire Goa, some parts of Maharashtra and Andhra Pradesh, some more parts of Karnataka, remaining parts of Tamil Nadu” and much of the Bay of Bengal “during next two to three days.”
The department declared the onset only after its formal criteria were met. Convective cloudiness over the southeast Arabian Sea had increased over the preceding two days; westerly winds extended up to 4.5 km above mean sea level, blowing at 20-25 knots in the lower levels; and Kerala had recorded widespread rainfall, with isolated heavy falls, over the same period. The IMD’s threshold requires that, after May 10, at least 60% of 14 designated stations across Kerala and the adjoining coast report 2.5 mm or more of rain on two consecutive days, alongside the wind-depth and cloudiness conditions — a set of tests designed to rule out a false, pre-monsoon onset.
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The monsoon’s arrival comes under the shadow of a strengthening El Niño. The World Meteorological Organisation now puts the chance of El Niño conditions developing at about 80% for July and August, the core of the monsoon and the months that matter most for kharif sowing. The Pacific warming tends to suppress Indian rainfall, and the IMD has already pegged the season at a below-normal 90% of the long-period average. A poor monsoon would tighten reservoir discharge, slow groundwater recharge and strain a farm sector in which more than half the cropped area is rain-fed.
Meteorologists caution against reading too much into the late start. The onset date, they note, has historically little bearing on how much rain the season ultimately delivers — the monsoon has arrived early and still failed, and arrived late and still recovered. The cautionary example is 2015, the last year the IMD missed its onset forecast: that monsoon, too, reached Kerala behind schedule, and went on to close the season at 86% of the average, a deficient year deepened by El Niño.
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Published – June 04, 2026 01:05 pm IST
