Met Eireann has issued its second rain alert for today due to a risk of flooding.
Heavy pulses of rain may lead to flooding in places this Monday afternoon and evening, forecasters warn.
The status yellow alert has been updated for Donegal, Louth, and Monaghan today from now until 8pm.
The rain is expected to clear in the north west tonight.
The Ulster forecast says: “Rain will gradually clear tonight with some clear spells later. Where clear skies persist, a slight frost will develop. Lowest temperatures of 1 to 5 degrees, in no more than moderate westerly breezes.”
Tomorrow, Tuesday will be “largely dry” with some sunshine developing. Highest temperatures of 7 to 9 degrees in mainly light breezes.