Electrical storms swept north across the country during the early hours of this morning.
Between Ireland and the UK there were 13,000 recorded lightning strikes overnight.
This morning 4,000 homes in the southeast and along the south coast were without electricity, according to the ESB.
Crews have been working all day to restore power to customers. By mid-afternoon there were less than 200 homes without power in the Enniscorthy area and 300 in and around Killarney.
Although the risk of major thunderous activity has lessened, there is still a chance of more storms today and tomorrow. Some storms have continued in the north Irish Sea and along the east coast of Ulster.
Met Éireann is predicting scattered showers this afternoon that will be heaviest in the northwest. Some will be thundery. Temperatures will stay warm, with highs between 19 and 23 degrees.
Met Éireann meteorologist David Rogers noted warmer air temperatures over Ireland in the past week and that the atmosphere had destabilised over the past 24 hours.
Buoyant air coming up from the Bay of Biscay off the coast of France had triggered the storms.