Our Past Weather Statement section has been updated to include the latest September weather summary and the Summer 2018 weather summary. You can view this here https://www.met.ie/climate/past-weather-statements Select month/season from the dropdown.
A dry, cool month. The first week of September had high pressure dominating overall with weak weather fronts breaking through from time to time interspersed with some fine and dry days. The jet stream remained mostly to the north of Ireland. During the second week, the jet stream moved south over Ireland bringing more active frontal rain and showers at times in a westerly airflow. The third week was unsettled with a very active jet stream over Ireland. Two named storms, Ali and Bronagh plus Helene (remnants of a hurricane named by the National Hurricane Centre) passed close to or across Ireland between the 16th and 20th. Storm Ali brought widespread disruptive winds on the 19th with heavy rain in the North and West. The strong winds from Storm Bronagh passed Ireland to the east bringing heavy rain to the South and East on the 20th. High pressure re-established itself over Ireland from the 22nd, and became the dominant feature again up to the end of the month.
A summer of heatwaves and droughts. The summer of 2018 will be remembered for heatwave and drought conditions that affected many parts of the country. Intense thunderstorms were also a feature at the start of the meteorological season. Temperatures were above normal and rainfall amounts were below normal at most stations. Large blocking high pressure systems were the dominant feature of the summer. This kept the north Atlantic jet stream to the north of Ireland. The periods through the summer where high pressure dominated were the first two weeks in June, ending temporarily with the arrival of Storm Hector on 14th June. High pressure to the north stretched from the Azores to Scandinavia at times between the 21st June and the 14th July. This gave slack winds and very warm mainly dry conditions. In between these dry settled spells and especially during August a weak jet stream moved south over Ireland, with frontal troughs and showers crossing the country from time to time. However most of the rain fell in the north and west of the country.