Winter temperatures across the country are, are on the whole, expected to be cooler than last year. However in keeping with the trend in recent years, they are likely to be warmer than the 40-year ‘normal’ winter temperatures, according to a forecast by the India Meteorological Department. In general, maximum and minimum temperatures across most States are likely to elevated.
The season-averaged maximum temperatures are likely to be warmer than normal by 1°C in west Rajasthan, Haryana, Chandīgarh & Delhi, and Jammu & Kashmir and by 0.5C to 1C in Himachal Pradesh, Uttarakhand, Punjab, east Rajasthan, west and east Uttar Pradesh, Gujarat, Saurashtra & Kutch, Madhya Maharashtra, Marathwada, Vidharbha, west and east Madhya Pradesh, Arunachal Pradesh, Assam & Meghalaya and Nagaland, Manipur, Mizoram, Tripura.
The season-averaged minimum temperatures are likely to be warmer by 1°C in Gujarat region and by <0.5 C in Punjab and two subdivisions of West Bengal. The season-averaged mean temperatures are likely to be warmer than normal by 0.5C to 1C in all the subdivisions of the entire country, except Konkan and Goa, Karnataka, Kerala, Tamil Nadu, Rayalaseema and two subdivisions of West Bengal.
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The warming trends are part of a larger pattern stoked by global warming. Last winter was, on an average, about a degree warmer than the historical normal. Already this year is poised to break records. Between March and May this year, mean temperature was also warmer than normal with an anomaly of +0.77C, which (along with 2010) was the sixth warmest ever spring season since 1901.
The annual mean land surface air temperature averaged over the country during 2017 till October is +0.73C above the 1971-2000 average.
Experts have previously attributed these to signatures of global warming wherein maximum and minimum temperatures during winters have been rising.
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Cold waves
Cold waves — a characteristic mark of winters in north India — too may see a dip. According to the agency, there is a 40% chance that minimum temperatures will be above normal in the so-called “core cold wave zone” of Punjab, Himachal Pradesh, Uttarakhand, Delhi, Haryana, Jammu & Kashmir, Rajasthan, Uttar Pradesh, Gujarat, Madhya Pradesh, Chhattisgarh, Bihar, Jharkhand, West Bengal, Odisha and Telangana and Maharashtra.
“These are signs of global warming and in keeping with trends observed in other parts of the world too,” said K.J. Ramesh, Director-General, India Meteorological Department. Other than global warming, ocean conditions over the equatorial Indian and Pacific oceans also contribute to the year-to-year variability of cold waves over the country.