It is the first snow warning of the winter.
Earlier this week, Met Éireann issued a nationwide weather advisory, stating that it would be "Much colder for the rest of the week, with sharp to severe frosts and icy stretches," and that advisory is in place until 11.59pm on Friday evening.
Today (Thursday, December 3), there is a snow and ice warning in place for one county, and Met Éireann have issued the warning to remain in place until 11.59pm tonight.
Donegal is told to expect "heavy wintry showers of hail, sleet and snow", as well as "reduced visibility and accumulations likely in places."
The Met UK issued a similar warning for Antrim, Fermanagh, Tyrone, and Derry, but that warning began at 12.01am this morning, and expired at 8am.
Meanwhile, the rest of the country should expect temperatures to dip to between 0 and 2 degrees tonight and Friday night, before dropping to as low as -3 degrees on Saturday night.