Wrap up warm because the first sharp cold snap of the season is set to last for the next few days.
A bitter start to the week will give way to more wet and windy conditions in the second half, according to Met Eireann.
Today, the overnight cold and frosty conditions will lift quickly, with some hazy sunshine and it will start dry and bright in the east. However, rain will spread westwards across the country throughout the day.
Tonight is set to be very cold again, with frost in the north and west, though temperatures will hover at between three and five degrees elsewhere.
Tomorrow's weather is set to be showery at times, mostly in coastal areas but becoming largely dry with some bright or short sunny spells developing. Highest temperatures will be between just five and eight degrees, with some light winds.
Tuesday night is also set to be very cold and frosty, with temperatures below freezing in many places and a risk of icy patches on the roads.
Wednesday will stay mostly dry but with little or no wind, fog may linger, especially in the Midlands, according to a Met Eireann forecaster. The weather is set to change on Thursday, with increasing southerly winds bringing cloud and rain in from the Atlantic. The east will stay mainly dry throughout the day, with milder temperatures.
Friday is likely to see rain in the south and in the west, sometimes heavy, and it will be another mild and breezy day.
Changeable and unsettled weather is expected for the weekend with nighttime temperatures back below freezing again.
The chilly conditions come amid warnings that Ireland could be facing the coldest winter since 2010, with Russian winds set to sweep in with a "beast from the East".
In a 90-day forecast, the UK Met Office predicted biting easterly winds in the New Year with the risk of freezing conditions.