Mild and Dry overall
The first week of January was changeable with low pressure to the north and west and high pressure to the south and southeast. Relatively weak weather fronts crossed the country from time to time in a mild south-westerly airflow, with dry periods in between. The second week was more unsettled with active lowpressure systems dominating our weather in a mostly westerly or south-westerly airflow. One such system, Storm Brendan, brought the strongest winds of the month on the 13th, including a squall line which crossed the country from west to east with embedded thunderstorms. It remained very unsettled and windy up to the 16th. The rest of the third week saw high-pressure building over Ireland, which intensified to near record levels on the 20th and brought some cold, crisp, mostly sunny days with frost and fog at night. Anticyclonic gloom took over from the 21st when a weak weather front brought a lot of cloud into the highpressure system over Ireland. Several dull days followed, along with some dense fog and drizzle up to the 25th. Atlantic weather fronts broke through on the 26th in a westerly airflow and introduced a fresh and cold polar maritime air mass, originating from Greenland. This brought wintry showers and frost at night, with lying snow in places, especially in the West and North. A weak warm front brought milder air in from the southwest on the 29th and the month finished mild and changeable once again.
The full report is available here