According to Met Eireann, temperatures are set to drop to as low as -1C this week

"Dry today with a mix of cloud and sunshine. The best of the sunshine will be in the south and east of the country, with cloudier conditions in the west and north. After a chilly start temperatures will rise to 10 to 12 degrees in light northwest or variable breezes." All grand, but tonight will see a drastic drop in temps. "Tonight will be dry as well with mostly clear skies in the south and east with lowest temperatures of -1 to 4 degrees and a slight grass frost. Cloud will increase in the west and north overnight and it will be less cold there with 3 to 6 degrees. Light southwest winds will increase moderate to fresh on northwest coasts." "On Tuesday after a bright start, cloud will thicken from the west and it will become breezy later as well. It will stay largely dry though. Highest temperatures of 11 to 13 degrees. Southwest winds will increase moderate to fresh later in the day." It will warm up slightly, but it's looking like it will be under 10C for the rest of the week. "On Wednesday, rain in the west will gradually spread across the country. The rain will turn heavy at times in the west. It will become breezy as well with fresh and gusty southerly winds. Early Wednesday night the rain will clear with just a few showers following. Minimum temperatures of 4 to 7 degrees in light westerly breezes." "On Friday, it seems likely that rain moves up from the south, possibly turning heavy. In this scenario it will become milder as well from the south as the day goes on. Strong winds are also possible with the rain." Gross.