Weather forecasters are predicting winter may finally arrive today with snow expected in some places.
Met Eireann confirmed tonight would be very cold with showers affecting the north and west, some falling as hail or sleet and with some snow possible in places.
Forecasters predicted the rest of the country will be mainly dry with clear spells and sharp to severe ground frost setting in.
Met Eireann warned there will be a danger of icy roads.
Last month was the warmest on record for almost four decades in some western parts of Ireland. Weather stations at Valentia Observatory in Co Kerry and Belmullet in Co Mayo had their warmest October since 1969.
Average air temperatures throughout the country were close to two degrees higher than for the period between 1961 and 1990.
Valentia recorded is wettest October day for some 19 years on the 25th with a rainfall of 55mm. Dublin Airport had its sunniest October since 2000.
The mild temperatures last month followed the warmest September on record for many parts of Ireland.