Delhi facing its longest cold spell in 22 years, mercury dips to 5.7 degrees

Thus far, Delhi’s cold spell this December has been eight days if only Safdarjung station is considered and eleven days if other stations are considered. In 1997, there was a cold spell for 13 days in December.

With most weather stations, other than Safdarjung, recording on Tuesday, maximum temperatures at least 4.5 degrees Celsius lower than the normal maximum temperature at this time of the year, Delhi is going through its longest cold spell in 22 years.

Labourers warm themselves around a bonfire on a cold winter morning, at Mahila colony Market in East Delhi on Tuesday, December 24.((Photo: Sonu Mehta/ Hindutsan Times))

Thus far, Delhi’s cold spell this December has been eight days if only Safdarjung station is considered and eleven days if other stations are considered. In 1997, there was a cold spell for 13 days in December. “Delhi so far has recorded longest and extreme cold day spell in December month, since 1997,” the India Meteorological Department (IMD) said on Tuesday.

Since 1993, Delhi has seen cold days only in 10 years, and had a cold spell only in four (before this year) — 1997, 1998, 2003, and 2014.

The IMD statement added that a cold spell has prevailed over north Rajasthan and Uttar Pradesh during the same period from December 15 to 24; in parts of Bihar between December 17 and 22 and over northern parts of Madhya Pradesh between December 17 and 20.

Delhi recorded a cold day on Tuesday also with all stations in Delhi except Safdarjung station meeting the criteria (a maximum temperature 4.5 degrees C below normal). The maximum temperature at Safdarjung was 17.2 degrees, 4.2 degrees below normal while the minimum temperature was 5.7 degrees C, 2 degrees below normal. “All stations in Delhi except Safdarjung registered a cold day. The maximum temperature improved marginally at Safdarjung because the cloud cover cleared briefly in the day allowing in sunlight,” said Kuldeep Srivastava, head of Regional Weather Forecasting Centre (RWFC).

The reason cold spells are uncommon is because they are triggered by multiple factors, all acting together. “Wind direction should be northwesterly, bringing cold air from the snow-clad regions; there should be a cloud layer blocking sunlight; and there should be fog in the morning. These factors don’t happen together at the same time every year,” added Srivastava. “We are seeing the 1997 situation again mainly because of a very strong western disturbance (that happened) around December 12 and 13. There have been low clouds blocking the sun since then, so the situation isn’t improving,” explained RK Jenamani, senior scientist at the National Weather Forecasting Centre (NWFC).

The main difference between a cold spell and a cold wave is that the former involves lower-than-normal maximum or day temperatures for two-three days in a row while the latter involves lower-than-expected minimum or night temperatures for at least more than one day. In the coming days we could see both, experts say.

“Cold day or severe cold day conditions will continue till December 28 in Delhi following which there is likely to be a cold wave in Delhi as per our forecasts. This is mainly because the wind direction will be northwesterly till then. On December 28 there can be a change in wind direction to easterly, temporarily, but night temperatures will continue to fall,” said Srivastava. A severe cold day is when maximum temperatures are 6.4 degrees C lower than normal.

IMD’s Tuesday bulletin said: “due to favourable meteorological conditions, dense to very dense fog in the morning hours and cold day to severe cold day conditions is very likely over Delhi in the next two days.”

Dense to very dense fog in the morning hours and cold day conditions are also likely over Uttar Pradesh during the next five days.

“Due to low-level cloud cover and light to moderate lower level north-northwesterly winds over northern parts of the country, cold day to severe cold day conditions are very likely to continue to prevail over northern parts of India till December 26. Its intensity and spread is very likely to decrease on December 27 and 28 and likely to abate thereafter,” IMD’s statement on Tuesday added.

The wind speed on Tuesday was also very low at only 6 to 8 kmph in Delhi making conditions unfavourable for dispersion. The AQI reading was 383 — in the very poor category, almost bordering severe.