Met Éireann has issued a status yellow warning for fog in Galway this morning.
The forecasters say some areas of dense fog may cause difficult travel conditions.
The warning, affecting all counties in the Republic, is expected to be lifted at 10am this morning.
When the fog lifts, there will be sunny spells with a chance of just a few isolated showers.
Highest temperatures will be between 8 and 10 degrees in moderate west to northwest breezes.
Tonight will start cold, dry and clear with just a few mist patches. Frost will develop in places as temperatures fall to between -1 and +3 degrees.