Widespread frost and ice to start on Friday, with temperatures struggling to reach afternoon highs of just 1°C to 3°C.
There will be some sunny spells, but a few wintry showers will affect Connacht, Ulster and coastal parts of Leinster.
A severe frost will set in quickly after dark on Friday evening.
By night, predominantly dry, with just a few patches of freezing fog. Minimum temperatures of -7°C to -3°C.
Frost and ice clearing slowly on Saturday to leave a mostly dry day, with sunny spells.
Cloudier in the northwest, with the chance of patchy rain there.
After a cold start, maximum afternoon temperatures will range from 2°C to 5°C.
There will be some patches of light rain or drizzle in the west and north on Saturday night, but dry in most areas.
Minimum temperatures -2°C to 4°C, coldest in the south, with another fairly widespread frost away from Atlantic coastal areas.
Many areas will be dry on Sunday, with a mix of cloud and some bright spells.
Patches of rain will drift along Atlantic coastal counties at times, with more persistent rain on the north coast. Maximum temperatures of 5°C to 8°C.
Cloudy overnight, with further patches of light rain in parts of the west and north, but mostly dry further south and east.
Minimum temperatures of 3°C to 7°C.
Scattered outbreaks of rain and drizzle for early next week, with a nice lift in temperatures reaching 10°C to 12°C.
This is an important time of the year for planning out the year ahead and to analyse crop and product options, writes Andy Doyle.
With sheep factory prices on the rise again, some farmers may be assessing the quality of their ewe lamb replacements, with a view to cashing in on those that do not meet the grade, writes Darren Carty.
With spring calving just weeks away, suckler farmers should be starting to feed pre-calving minerals to cows, writes Kieran Mailey.
Aidan Brennan says now is the time to give certain vaccines to dairy cows.