By Purushottam P. Khatri

Kathmandu, Dec. 28: Minimum temperature in Kathmandu during the winter season over the last six years has been found plummeting, according to the records of Meteorological Forecasting Division (MFD).
Winter season in Nepal normally begins from the second week of December and lasts till mid-February. According to MFD under the Department of Hydrology and Meteorology, the average minimum temperature of Kathmandu for the month of December is usually 3.7 degree Celsius. On Wednesday (December 25, 2019), Kathmandu had this season’s lowest minimum temperature at 0.9 degree Celsius.
However, senior Meteorologist Min Kumar Aryal talking to The Rising Nepal on Friday said that there was the record on January 7, 2018, that the minimum temperature sharply came down up to 0.0 degree Celsius.
Within next two weeks, Kathmandu’s minimum temperature may plummet further- to minus level from next week, with the likelihood of winter rainfall due to westerly wind. If this happens, the Valley’s minimum temperature may experience below freezing level, Aryal said.
A glance at Kathmandu’s minimum temperature records, from 2014 to 2019 A.D, shows the minimum temperature was going down every winter season.
According to the MFD’s records, in 2014, the minimum temperature of Kathmandu was recorded 1.7 degree Celsius on December 12, 0.2 degree Celsius on December 26 in 2015, 2.2 in December 23 in 2016.
Also, in the years 2017, 2018 and 2019, the lowest minimum temperature was recorded 0.4 on January 14, 0.0 on January 7, and 0.5 on December 25, respectively. Except in the year 2016, all other years of minimum temperature were recorded at almost one or zero degree Celsius.
Meteorologist Aryal attributed severe chilly condition in Kathmandu due to effect of jet streams, the fast flowing, narrow and meandering air current in the atmosphere that can be found up to 15-16 kilometers above.
The second reason behind increasing cold in Kathmandu is due to wind that blow from north-western region of Nepal. This wind develops in the Mediterranean Sea and blows abutting Jammu-Kashmir, Himanchal provinces of India. The third reason is the seasonal one that happens after winter rainfall.
Meanwhile, senior meteorologist Rajendra Kumar Shrestha, who retired from the MFD some seven years ago, said Kathmandu for past three years had been witnessing some imbalanced minimum temperature.
He predicted that from next week of Thursday to Friday, Kathmandu again likely to have second winter rainfall of this season, and if this happens, Kathmandu’s minimum temperature might go down up to minus level.
From coming Sunday, western Nepal will gradually start witnessing cloudy weather and likely to have rainfall on Monday to Wednesday.
According to him, minimum temperature of Kathmandu depleted so fast in the past two weeks due to first winter rainfall on December 13. Westerly wind is again go to develop so fast within two weeks of the first winter rainfall, which is also leading to sharp decline in minimum temperature, Shrestha said.
During this lifetime of the job as meteorologist, he had never seen such fast frequency of the development of westerly wind that had been causing frequent rainfall in winter season.