Met Éireann is advising that it could be a very wet Christmas for parts of the country.
A status yellow rainfall warning is in place for Connacht, Donegal and Clare until 7am tomorrow (Christmas Day).
Forecasters say rainfall accumulations of 25 to 35mm are likely today and overnight.
Meanwhile, a status yellow weather advisory for Munster and Leinster is in place between 4am and 8pm on Christmas Day.
Met Éireann says rain is likely to become persistent and heavy during Monday.
Nationally, they say brighter weather with scattered showers will develop elsewhere in the country on Christmas Day, adding that a few of the showers could fall as hail or sleet.
Cold weather is expected, with afternoon temperatures of 5 to 7 C.
Temperatures are expected to fall below freezing again overnight on St Stephen's Day and Wednesday.