The minimum and maximum temperatures have stayed above normal for the last few days in Bengaluru because of clouds brought in by a cyclonic system on the Coromandel Coast. It will stay this way until December, and the city is likely to get light to moderate rains in the next few days.
The phenomenon has worsened the air quality in many parts of the city with the Air Quality Index hitting the 200 mark.
The maximum and minimum temperatures recorded by the IMD's Bengaluru City station on Wednesday were 27.4°C and 17.8°C, 0.8°C and 1.8°C above normal, respectively. The temperatures at HAL airport were 27.6°C and 16°C, up 1.4°C and 0.8°C from normal, respectively.
A Prasad, who heads the IMD's meteorological centre in the city, attributed this to prevailing high clouds. "The depression in the Bay of Bengal has intensified into a deep depression and is on course to become a cyclonic storm and hit the Tamil Nadu and Puducherry coasts by Thursday morning. As a result, we are experiencing a generally cloudy sky. This is preventing the temperatures from dropping," Prasad explained to DH.
Cloudy weather will continue until December 11, he added.
According to Prasad, this is not a typical winter phenomenon when there's continuous fog in the morning, visibility is poor and the mercury drops sharply. "We'll have typical winter conditions in the third week of December when there will be clear skies," he added.
The northeast monsoon, Bengaluru's second rainiest season, has also persisted. Light to moderate rainfall has been forecast for the next two days, he added.
Air quality dips
Meanwhile, cloudy weather conditions have worsened the city's air quality. Many areas reported an Air Quality Index of 200 or above, which is categorised as poor.
Jayaprakash Nayak, Senior Scientific Officer, Karnataka State Pollution Control Board (KSPCB), said the cloudy weather had led to a phenomenon called the winter inversion effect.
"The formation of a blanket in the atmosphere prevents sunshine from reaching the ground and stops wind movement. As a result, there's no air dispersion and pollutants don't get dispersed," he said.
Nayak clarified that this is a temporary phenomenon and that Bengaluru's monthly AQI has never crossed into "poor" territory. "The AQI dips in some areas only on some days," he added.