Met Eireann has issued a Status Yellow rainfall warning for Donegal due to a risk of heavy downpours, thundery showers and hail.
Donegal is the only county in Ireland to have a colour-coded warning today.
Today and overnight will bring heavy or prolonged showers of rain or hail to Donegal to give rainfall accumulations of 25 to 40 mm. Accumulations will be possibly higher in some mountainous areas, according to forecasters.
Motorists are warned to be vigilant for spot flooding and hazardous driving conditions.
The rain warning is in place from 7am this Sunday morning until 6am Monday.