Monsoon set to hit Kerala in days as IMD warns of storms, heatwave conditions

NEW DELHI: The southwest monsoon is expected to reach Kerala within the next two to three days, marking the start of a season critical to India's farm economy, even as the India Meteorological Department (IMD) forecast widespread thunderstorms and pockets of heavy rainfall across several regions this week.

The weather office said conditions remain favourable for the further advance of the southwest monsoon into parts of the southwest and southeast Arabian Sea, Lakshadweep Islands, parts of Kerala and Tamil Nadu, additional areas of the southwest, west-central, east-central and northeast Bay of Bengal, and the remaining parts of the southeast Bay of Bengal over the next two to three days.

The normal onset date of the southwest monsoon over Kerala is 1 June. In 2025, the monsoon arrived early on 24 May.

The monsoon, driven by branches from the Arabian Sea and Bay of Bengal, advances northward in stages before covering the entire country by mid-July.

India remains heavily dependent on southwest monsoon rains, which account for more than 70% of the country's annual precipitation. Adequate rainfall supports agricultural output and rural demand. With only around 55% of India's net sown area currently irrigated, a large share of farmland continues to depend on rainfall, making any shortfall a potential source of higher irrigation costs for farmers.

In its updated long-range forecast released Friday, the IMD said rainfall during the June–September monsoon season is likely to be 90% of the long-period average (LPA), down from 92% projected in April. Rainfall is considered normal when it falls in the 96–104% range.

Separately, the IMD forecast isolated heavy rainfall accompanied by thunderstorms over Northeast India and south peninsular India through the week. Moderate to severe thunderstorm activity, accompanied by squally winds of up to 70 kmph and isolated hailstorms, is likely over northwest, central and adjoining east India.

States across northwest and central India could face gusty winds, lightning and localised disruptions from storm activity, the department said.

Temperatures to rise in north, east India

Despite scattered rainfall and thunderstorm activity in some regions, maximum temperatures are expected to rise across parts of northern and eastern India.

Northwest India is likely to see temperatures increase by 4-6 degrees Celsius during the week. In east India, temperatures are expected to rise by 2-3°C until 1 June before stabilizing through the rest of the week.

Maharashtra may see temperatures fall by 2-3°C until 5 June before remaining largely unchanged. Gujarat is expected to witness little change until 2 June, followed by a gradual decline of 2-4°C between 3 and 7 June. No significant change in maximum temperatures is expected across the rest of the country until 7 June.

The IMD has also issued a heatwave warning for Bihar between 3 and 7 June, while hot and humid conditions are expected to persist across parts of the Northeast and eastern India.

Hot and humid weather is likely over Arunachal Pradesh until 3 June; Assam, Meghalaya, Nagaland, Manipur, Mizoram and Tripura on 2 June; Sub-Himalayan West Bengal and Sikkim until 3 June; and Odisha from 2 to 5 June.

Meanwhile, maximum temperatures on 31 May ranged at 40-43°C across many parts of Vidarbha and Telangana, some pockets of Gujarat, Coastal Andhra Pradesh and Tamil Nadu, and isolated areas of Rajasthan, Madhya Pradesh, Chhattisgarh and Marathwada. Most other parts of the country recorded temperatures between 32 and 40°C, except the Western Himalayan Region, parts of Arunachal Pradesh and Sikkim, and isolated pockets of south peninsular India and the island regions, where temperatures remained below 32°C.

The highest maximum temperature recorded on 31 May was 43.8°C at Washim in Maharashtra.