After a brief delay, the southwest monsoon is expected to make its onset over Kerala around June 4, 2026, according to the India Meteorological Department (IMD), marking the official beginning of India’s rainy season.
However, the IMD does not declare the onset of the monsoon based on rainfall alone. The weather agency follows a set of meteorological parameters before officially announcing that the monsoon has arrived over Kerala.
The 3 Key Conditions IMD Monitors
The IMD closely tracks three major conditions before declaring the onset of the southwest monsoon over Kerala.
The first requirement is widespread rainfall activity across designated monitoring stations in Kerala over consecutive days.
The second condition involves the strengthening of westerly winds over the Arabian Sea, indicating that moisture-laden monsoon currents have advanced into the region.
The third key parameter is the presence of deep clouding and organised convective activity, which meteorologists monitor through weather observations and satellite data.
With rainfall activity intensifying over southern India, conditions are gradually turning favourable for the official onset announcement.
Heavy Rainfall Forecast Across Southern States
The IMD has forecast widespread rainfall activity across southern states over the coming week, with Kerala expected to receive the maximum impact from the advancing monsoon.
Isolated places in the state are likely to witness heavy to very heavy rainfall between 7 cm and 20 cm during the next six to seven days.
The weather agency has also predicted isolated heavy rainfall over parts of Tamil Nadu and Karnataka as monsoon winds strengthen over the Arabian Sea and continue their northward advance.
Why Monsoon Onset Matters For India
The arrival of the southwest monsoon is a crucial development for the country, as nearly half of India’s farmland depends on seasonal rainfall for irrigation.
The monsoon also replenishes reservoirs, supports hydropower generation and provides relief from intense summer temperatures across several regions.
Meteorologists are expected to closely monitor the monsoon’s movement in the coming days as it advances beyond Kerala into other parts of southern and northeastern India.
Thunderstorm Alert Across Several Regions
Alongside the advancing monsoon, the IMD has warned of moderate to severe thunderstorm activity across many parts of northwest, central and eastern India, as well as south Peninsular India, during several days of the coming week.
These thunderstorms may be accompanied by squally winds reaching speeds of 40 to 50 kmph, posing risks to outdoor activities, temporary structures, power lines and agriculture.
Residents in affected areas have been advised to remain alert and follow local weather advisories.
Relief From Heatwave Conditions Likely
In northwest India, including Delhi-NCR, Rajasthan, Punjab and Haryana, thunderstorms and gusty winds are expected to continue bringing relief from the recent spell of extreme heat.
Similar weather conditions are likely across Madhya Pradesh and Chhattisgarh, while Bihar, Jharkhand and West Bengal may also witness thunderstorms and intermittent rainfall.
The forecast comes after several days of widespread pre-monsoon thunderstorm activity across the country, which has already contributed to a drop in maximum temperatures at many places.
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With heavy rain, thunderstorms and strong winds expected across multiple regions, India is likely to witness an active start to the 2026 monsoon season.
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