Summer on the wane in Kerala, signalling mild weather and monsoon ahead

Kerala's summer season ends with relief from oppressive heat, as monsoon approaches and above-normal rainfall predicted.

The peak summer season is nearing to a close in Kerala even as the monsoon is on its way to the State. After two oppressive heat years, temperature mostly remained within limits during this peak summer season, with mercury hovering below the 40-degree Celsius mark across Kerala. In 2024 and 2023, temperatures crossed 40 degrees Celsius in Palakkad and at Vellanikkara in Thrissur.

This year, in the beginning of the summer season, temperature, however, recorded 40.4 degrees Celsius and 40.2 degrees Celsius, twice, in Kannur airport in February. But the data from the airport was not fully reliable, according to India Meteorological Department (IMD) sources, as the instrument is “not placed at the right location” and the hot air blowing out of the heat source of runway could drive the temperature values up.

Further, the summer rains that lashed Kerala at frequent intervals during this summer helped the State heave a sigh a relief. Kerala has netted a total of 213.1 mm rain against the average of 153 mm rain from March 1 to May 3, around 39% surplus, making the year one of the relatively wet summer seasons in the past five years.

In addition, the monsoon is on its way to Kerala as hardly about 22 days are left for the southwest monsoon to enter the normal onset window in the State, which is around June 1, with a standard deviation of about 7 days, meaning normal onset can happen any time between May 25 and June 8.

Ahead of the season, the maximum day time temperatures also dropped to normal and below-normal at several places aided by summer showers, which signals the milder weather ahead, marking the end of oppressive heat.

According to senior IMD scientists, the present atmospheric conditions are also favourable for the continuance of the summer rains with a north-south trough over the land, a prominent feature during the summer that draws moist air from the Arabian Sea and the Bay of Bengal. This will mingle with the ascending hot air over land, creating convective clouds over the land every afternoon, thus likely triggering summer rains by afternoon.

However, it is a matter of concern when the IMD fails to issue proper alerts on time. For instance, Vellayani and Chakka in Thiruvananthapuram recorded 99 mm and 75.5 mm of rain, respectively, on Friday (May 2), followed by Punalur with 64.5 mm of rain. The IMD, which had issued a green alert for Friday at noon, upgraded it to a yellow alert only by 7 p.m. after heavy rain lashed these regions.