Saturday will see outbreaks of the rain in the far west move slowly eastwards through the day.
The rain will be heavy and persistent in places at first but will tend to ease and become patchier by evening.
It will be mainly dry elsewhere with largely cloudy skies, although some bright or sunny spells are likely for some.
Winds will strengthen in the west, with temperatures close to average for most.
Top temperatures of 10 Celsius (50F).