Bengaluru's winter paradox: Warmer nights, cooler days

Bengaluru: After several warm days, the weather became chillier in the city on Monday, as the maximum temperature stood three degrees below normal. 

The India Meteorological Department's (IMD) Bengaluru city observatory recorded a maximum temperature of 23.6°C, substantially lower than December's mean maximum temperature of 26.9°C. 

But the opposite was true of the minimum temperature, which stood at 19°C, nearly 3°C higher than the mean of 16.4°C. In effect, the difference between maximum and minimum temperatures (diurnal variation) dropped to less than 5°C, leading to warmer nights/mornings, but colder days. 

A Prasad, who heads the IMD's meteorological centre in Bengaluru, attributed the phenomenon to the lingering effects of the northeast monsoon and an upper air cyclonic circulation centred around the Comorin area, India's southernmost tip. 

"This upper air cyclonic circulation is behind the unprecedented rainfall in southern Tamil Nadu. It has also caused overcast conditions in South Interior Karnataka and parts of North Interior Karnataka," he told DH. 

In many parts of the city, there was hardly any sunlight. But the minimum temperature didn't fall because of cloudy skies and strong winds travelling at 30 kmph, he added. 

The situation is expected to change from Tuesday onwards as the upper air cyclonic circulation weakens. "The maximum temperature will rise to 26°C, while the minimum will fall to 18°C," he said. "Nevertheless, this winter won't be harsh. There will be no biting cold. The minimum temperature won't fall to 14°C or lower." 

Vulnerable people, including the elderly and children, will still have to take precautions, he added. 

In January — the peak winter month in Bengaluru — late nights/early mornings will become chillier while days will become warmer, Prasad said.