Solar generation in April 2026 started slowly but finished strongly.
The first two thirds of the month were poor in generation terms. A succession of Atlantic low pressure systems, including Storm Dave on 4th April, brought persistent cloud cover, heavy rain and high winds across Ireland. Overcast skies are the single biggest enemy of solar output, and with cloud sitting over the country for the best part of a fortnight, generation during this period will have been significantly reduced, particularly for sites in the west.
Things shifted around 18th April. High pressure established itself over the country and stayed, bringing clear skies and strong peak sun hours for the final stretch of the month. This is where April recovered its ground. At this time of year, the sun is climbing noticeably higher in the sky compared to winter – irradiance levels in late April are roughly double what they are in December. So every clear day in this period was generating optimally.
The sunshine data reflects this upward trend. Met Éireann recorded totals between 114% and 128% of the long-term average across national stations, with Casement Aerodrome (Dublin) reaching 201.5 sunshine hours and Johnstown Castle (Wexford) topping 209 hours. This volume of solar exposure is equivalent to 138.6 Peak Sun Hours (PSH) for the month, which translates to 138.6 kWh for every kWp of installed capacity. This performance compensated for the cloudy start to the month and underscores the generation potential of the region’s solar resource.
The one caveat is geography. Rainfall was 113% of normal nationally, with the bulk of it falling in the west. Sites in Connacht and west Munster will have seen a more pronounced dip in generation during the unsettled period compared to sites in Leinster and the southeast, which were partly shielded from the worst of the cloud and rain.
May and June are typically the strongest months of the year for solar generation in Ireland – longer days, higher sun angles, and the best chance of sustained high pressure. April’s strong finish points in the right direction.