The minimum temperature in Kathmandu dipped to 2.2 degrees Celsius—the lowest so far this winter—on Wednesday morning, as the cold weather gripped the country.  The previous lowest minimum temperature in Kathmandu Valley was 2.8 degrees Celsius on December 16.

According to Barun Paudel, meteorologist with the Meteorological Forecasting Division (MFD), such erratic drop in temperatures was normal at this time of the year, which is the pick of the winter.

“We are in the middle of the winter season. Such flux in temperatures is well-expected at this time—between December 15 and January 15,” explained Paudel.

The MFD has attributed the sudden drop in temperatures to the north-westerly wind which saw thick fog enveloping most parts of the country.

“North-westerly wind that has entered via Himalayan ranges has led to sudden drop in temperatures,” he said.

Also, the radiant cooling system that is activated has brought about dip in temperatures in areas like Kathmandu Valley.

“The ground gets cooled down over the night, which is longer during winter. The cooled surface causes fog in the morning. However, they disappear later as the sky becomes clearer with no cloud that could work as a blanket,” he said.

According to the MFD bulletin of Wednesday morning, temperatures have dropped in many places across the country.

As Kathmandu recorded its lowest temperature of the season on Wednesday, Jumla witnessed -6.4 degrees Celsius—the lowest recorded temperature for the country, Dipayal (1.4 C), Dadeldhura (2.5 C), and Birendranagar (2.9C).

 The normal life was affected in the southern plains due to continuous thick fog. The local authority in Dhanusha district has decided to close all public schools from Wednesday temperatures dropped several notches, intensifying chilly weather conditions.

People were forced to begin their day late due to fog, which also inconvenienced motorists and other commuters due to low visibility.

The District Education Officer Yam Bahadur Khadka said the authority had decided to shut schools earlier due to cold, although the winter vacation in the district starts from mid-January.

The MFD has, however, said that the ongoing weather condition in the Tarai was not cold wave, but thick wave, which dissipates later in the afternoon.

“The dense fog seen in the Tarai is similar to the fog in the Gangetic plains across the border in the Indian states of Uttar Pradesh, Bihar. The thick fog in the Tarai is advection fog which has horizontal movement and have entered our side from India,” said Paudel.

For cold wave, such fog should persist for at least 48 hours and the temperatures should decrease.