The mercury stayed under 20 degrees Celsius for the second consecutive day as the city remained cloaked in fog and swept by chilly winds.
The maximum recorded on Thursday was 19.6 degrees Celsius, six notches below normal. Wednesday’s highest recording was 19.8.
While the minimum temperature is an indicator of how cold the night was, the maximum is a pointer to how cold the day was. On Friday, the maximum and minimum both are expected to rise by a degree.
“There was fog in the city from the morning till well past noon on Wednesday and Thursday. The fog cover kept the day temperature in check. Friday will be less foggy and the day temperature will gradually rise,” said G.K. Das, a meteorologist at India Meteorology Department, Calcutta.
A mass of moist air that had originated in north India and was blown east along the Ganga, condensed into fog in the morning on both Wednesday and Thursday.
Such fog is called advective fog. It hangs in the air longer than normal fog as it reaches a greater height and sunlight cannot penetrate it.
The foggy layer above the city ensured that the chilly wind from the north blew close to the ground.
A combination of chilly winds and overcast sky accentuated the feeling of cold beyond the mercury readings.
“I left for my office on my motorbike at 10am in a T-shirt and sweatshirt but had to rush back as I could feel the cold wind in my bones. I had to put on a heavy jacket before venturing out again,” said trader Sharat Singh, 40.
Experts said when a wind as strong and cold as Thursday’s blows, the temperature we feel — the “real feel” temperature — is two degrees below normal.
Since Thursday’s minimum was 12.5, the “real feel” temperature was 10.5, the season’s lowest so far. The season’s actual lowest — 11.3 — was recorded on January 9.
“There were cold winds blowing throughout the day. Even at 2.30pm, the wind was blowing at 6kmph from the north north-west direction. On Wednesday, the maximum wind speed was 4kmph,” said the official.