Winter is likely to be mild with fewer cold wave days following record high temperatures in the autumn months of October and November, the India Meteorological Department (IMD) said on Monday.
November 2024 was the second warmest for India since 1901 in terms of day temperatures and third warmest for mean temperatures. For northwest India, it was the warmest November since 1901 for mean temperatures and second warmest for day and night temperatures.
Also read: Cyclone Fengal: Buses submerged as floods hit Tamil Nadu, relief operations underway
The country experienced its warmest October in 123 years, with unprecedented night-time and mean temperatures. October marked the fourth consecutive month of record-breaking night-time temperatures since measurements began in 1901, following similar records in July, August and September.
The weather office has forecast above-normal temperatures over most parts of the country from December to February, except south peninsular India where below-normal temperatures are likely. Below-normal cold wave days are expected over most parts of northwest, central, east and northeast India.
“During the upcoming winter season (December 2024 to February 2025), above-normal minimum temperatures are likely over most parts of the country. Above-normal maximum temperatures are likely over most parts of the country except most areas over south peninsular India, where normal to below-normal maximum temperatures are likely,” IMD said.
Also read: Kerala weather: IMD issues red, orange alerts for 8 districts on December 2
A cold wave occurs when the minimum temperature falls below the 10th percentile of daily value and the daily minimum temperature is below 15 degrees Celsius. A cold wave event is declared if these conditions persist for three consecutive days. It is often also calculated as a negative deviation of more than five degrees in the night-time low (in the case of plains) and the minimum is below 10°C.
“Normally we see 5-6 cold wave days during December to February over the cold wave region which includes northwest, central, east and northeast India. This time, we can expect 2-4 fewer cold wave days compared to average,” said M Mohapatra, director general, IMD.
For the immediate future, in December, the weather office said minimum and maximum temperatures are likely to be above normal over most parts of the country, except some areas of central India.
Also read: Cyclone Fengal: IndiGo flight faces close call during landing attempt at Chennai airport | Video
November has been exceptionally dry, particularly for northwest India. During October 1 to December 1, there was 15% deficiency in rainfall over the country with 77.2% deficiency over northwest India. November saw 54.5% rain deficiency over the country with 79.9% deficiency over northwest India.
“There was no active western disturbance in November and there was only one cyclonic circulation or activity towards end of the month which is Fengal which impacted Tamil Nadu coast. So it has been very dry during past two months,” Mohapatra said.
The pattern of deficient rain is likely to continue over northwest India during December, though monthly rainfall over the country is expected to be above normal (more than 121% of Long Period Average). Normal to below-normal rainfall is likely over most parts of north and northwest India, and many areas of east and northeast India.
IMD data shows that the warmest Novembers have been in recent years – 2016 being the warmest, followed by 2024, 2000, 2007 and 2018. “Our data indicates that the top 5 warmest years have been recent years. It is the same trend for various regions including northwest India,” Mohapatra said.
He added that global agencies continue to get the La Nina forecast wrong. While La Nina was expected to emerge during October-December with 57% chance and persist through January-March 2025, it has not yet materialised.
La Nina is characterised by unusually cold ocean temperatures in the Equatorial Pacific, unlike El Nino which features unusually warm temperatures. Both typically develop in northern hemisphere’s spring-summer and peak in winter. For La Nina conditions, the Oceanic Nino Index must drop to at least -0.5°C or -0.3 degrees Celsius and sustain for a couple of months, which hasn’t happened this year.
In India, El Nino typically brings harsher summers and weaker monsoons, while La Nina is associated with strong monsoons, above-average rains and colder winters.
