Brace for a chilly weekend and get your woollies out as the minimum temperature is expected to reach a single-digit figure.

Patna woke up to its coolest November 26 in at least five years on Wednesday — the morning nip stood at 11°C.

Other districts sported a clear sky on Wednesday with low humidity conducive to lower minimum readings. Gaya witnessed the coldest morning in the state with the minimum temperature at 9.6°C, three notches lower than the respective normal. Bhagalpur, on the other hand, was warmer with the lowest level in the mercury column standing at 16.1°C.

Weathermen on Wednesday signalled that minimum temperatures across the state would drop below 10°C in 48 hours, courtesy favourable wind pattern and plummeting relative humidity.

Met officials predicted similar weather in the state for the next two-three days, with mist in the morning and evening. The forecast ruled out possibilities of cloud formation because of local effects or any system over the Bay of Bengal.

“Entire eastern India is witnessing lower temperature conditions owing to dryness in the atmosphere and lack of moisture feeding from the Bay of Bengal. Northerly winds blowing in Bihar and neighbouring regions for the past couple of days became stronger on Wednesday. If it continues to blow unabated in the absence of cloud formation, the minimum temperature across Bihar, including Patna, is expected to come down under 10°C,” said Ashish Sen, director, Patna meteorological centre.

Going by meteorological data, Patna usually experiences wintry conditions from the second week of December. However, for the past two years, winter has been officially setting in around the first week of December and it is at its peak normally between December 20 and January 10. This year, the season has crept in more than a fortnight ahead of schedule.

One of the most important reasons for the early onset of winter this time has been the lack of formation of any weather system in the Bay of Bengal. “A weather system like low-pressure area or cyclonic circulation over the Bay of Bengal at this time of the year could feed the air with moisture, which would lead to the formation of clouds, impeding the flow of the northerly wind. This in turn, would put a break on the plunging mercury,” said Sen.

The Met office chief added that though a system has formed in the Bay of Bengal, it is not strong enough to lead to cloud formation by the time it would make landfall in coastal Bengal region. The cloudless sky over Patna has played its part too, allowing the Sun to beat down and heat up the lower atmosphere. When this heat escapes at night, the temperature plunges.

Residents, too, have also started feeling the chill. Most people can be seen in their woollens throughout the day. School children and morning walkers have been the worst hit by the plummeting mercury.

“I used to go for morning walk around 6 in the morning till a week ago but now I have changed the timing to 7am owing to the shivery cold around the time of sunrise,” said Shailesh Kumar, a frequent morning walker at Patna zoo.

Flight operations

The advent of chilly days has also affected operation of flights at Jayaprakash Narayan International Airport. Owing to hazy skies, none of the flights are able to land or take off before 10am.

Consequently, airlines are also making required changes under their winter schedule. Air India has withdrawn its afternoon flight — AI 407/ 408 on the Delhi-Patna-Delhi route from November 6.

IndiGo would also cancel its morning flight 6E 494 operating on the Delhi-Patna-Ranchi-Delhi route from December 15.