Snow has been reported in Co Donegal this morning as a band of cold weather moves in to Ireland to replace last week's sunshine.
Sleet showers were also reported in Dublin city centre.
Met Éireann has said temperatures will be below average for the early part of this week, falling below freezing point tonight and tomorrow night.
The forecast is for a wet and breezy start this morning over Munster and much of Connacht and Leinster, turning more showery in the afternoon. In Ulster it will be cold and windy with some hail and sleet showers and the possibility of snow.
This evening will see temperatures plunge to as low as minus three degrees in many parts of the country.
Tomorrow and Thursday are also expected to be as cold in the evenings, although daytime temperatures may reach up to 11 degrees. Some clear spells are likely.
Met Éireann says over the Easter period temperatures will be in the low teens, which is normal for that time of year. However, it warns it may feel cooler at times due to fresh, northwest winds. Periods of rain are expected during Good Friday and Saturday, which are expected to clear by Easter Sunday.
Elsewhere, motorists in Britain faced difficult driving conditions today as snow blanketed parts of the country.
Around 20cm of snow fell in Aviemore in the Highlands overnight as an Arctic weather front bore down on the United Kingdom.
The Met Office issued severe weather warnings for all of Scotland, as well as parts of northern England, Yorkshire and Humber, and the East Midlands. Roads were closed in some areas due to the weather. The wintry blast comes just a week after record-breaking warm temperatures in north-eastern Scotland.
Last Tuesday, temperatures rose to 23.6 degrees in Aboyne, Aberdeenshire, marking a new high in Scotland for the month. Today the mercury dropped to minus 0.5 degrees overnight and was at 0 degrees at 6am.
Scotland’s central belt was also hit by the wintry weather, which will gradually creep into northern England, parts of Wales and the Midlands in the coming 24 hours. Forecasters predict that the snow will move south over the course of the day.
Nine hillwalkers who became stranded in Scotland’s Cairngorms have been rescued. A major rescue operation was launched this morning after the party, which included six teenagers, became stuck after heavy snow.
Additional reporting: PA