Forecasters have warned that mercury levels will start falling significantly throughout November, leading to a shivering run-up to Christmas, and an even bitterer spell throughout January.

Meteorologists said the combination of unusually-high Siberian snow cover this month, recent solar activity levels and volcanic emission patterns in Iceland, all point to a harsh winter ahead, with the severest spells of cold likely to occur between December and January.

James Madden, forecaster with Exacta Weather, said December could be as bitter as four years ago, the coldest in over 100 years in Ireland, while January could turn out to out to be one of the worst winter months on record.

He said: “As we progress throughout November, it is going to become gradually colder across many parts of Ireland, in particular from around the mid-month point when it is likely to become exceptionally cold at times.

“This early start to what is likely to be a harsh winter is also likely to be accompanied by a number of potentially widespread snow events within this period and into the start of December.

“The parts most at risk of experiencing snow within this period will be to the north and east of Ireland and some of this cold could prove to be quite significant at times, even across some much lower levels of the country.” He continued: “The worst-case and more plausible scenario could bring something on a similar par to the winter of 2009/2010, which was the coldest in 31 years, or an event close to 2010/2011, which experienced the coldest December in 100 years.

“However, the alternative and slightly more unfavourable scenario could see a winter period on a similar par to 2012/2013 developing, which would still support a colder and snowier-than-average winter throughout 2014/2015.

“If any month could prove to be very severe or potentially record-breaking in terms of the cold and snow episodes that are likely to develop, then January looks like being the main contributor for this on current indications.”

He added: “February and into spring may also not escape an extension of these waves of cold and widespread snow at times. However, there are some conflicting signals for December at present, which could introduce some milder and rather unsettled interludes of weather at times.”