If you find this December intolerable, blame it on abnormally prolonged day cold spells.

The state has so far experienced two spells of day cold conditions — the first from December 12 to 17 and the second started on December 20. It is still biting.

The fallout: dense fog, low minimum day temperature, deserted streets, and delayed trains and planes. Well, don’t forget the shiver.

The day cold condition prevails in a place when the maximum temperature goes eight to 10 degrees Celsius below the normal temperature and there is thick fog cover.

Explaining the reason behind the cold December days, Ashish Sen, director, India Meteorological Department, Patna, said: “The second day cold spell started only two days after the first. The lower level of atmosphere and the earth’s surface turned extremely cold in both the phases because there was not enough heat during the daytime. As the temperature dipped at night also, there was no heating of the atmosphere. These led to extreme chilly and uncomfortable conditions. Such cold was not observed in the city at least over the past 10 years.”

“A western disturbance prevailing over Uttar Pradesh is responsible for the dense fog cover and the day cold conditions over the northern and central parts of the state, including Patna. The maximum temperature of the day is expected to be eight to 10 degrees below normal, which is around 24-25 degrees Celsius at this time of the year,” Sen said.

Senior citizens of the state capital have echoed the claims of the weatherman. “December is a winter month but we never saw this kind of erratic weather. Usually this kind of cold weather conditions are observed in Patna around the second week of January. But this year, we are feeling the bite much earlier. People have to be cautious to protect themselves from the cold,” said septuagenarian R.C. Sinha, professor and head of zoology, Patna University.

On Friday, the minimum temperature in the city was 8.5°C. Gaya was the coldest in the state recording a minimum of 4.4°C.

The last December was warmer than this year’s. There was just one cold spell in the city in 2011. So were the preceding years.

In 2009, the maximum temperature in the state capital was above 22°C on all the days, except December 31. It was 19.8°C that day. The lowest minimum temperature of 6.4°C was recorded on December 27, 28 and 29.

The maximum temperature in the first fortnight of December 2008 varied between 22.1°C and 28.9°C. The maximum day temperature went below 20°C in the later part of the month only for five days.

December 2007 was also warm with the maximum temperature remaining above 22°C throughout the month. The temperature was above 22°C throughout the month except for December 31.

Silver lining

Weathermen claimed that December 31 and January 1 could be brighter. “The western disturbance has arrived two days earlier than expected and its impact on the state is expected to last for 60 hours. Thus, we expect that December 31 and January 1 will be warmer and brighter,” said Sen.