Gusts of up to 120km an hour and torrential rain caused massive disruption yesterday, including power cuts and travel delays.
One man was killed, while a female garda was seriously injured on traffic duty in Dublin. Some 15,000 homes in various parts of the country were without electricity for a time.
The sudden storms were caused by a deep depression moving across the country from the Atlantic.
Met Éireann said the unsettled weather is expected to continue in the early days of this week but wind speeds should not exceed those recorded yesterday.
Paul Bogues (46) died after being washed into the water in Ardglass, Co Down, on Saturday night. He was walking along the pier at Ardglass harbour when a high wave struck him and carried him into the sea.
Two friends held on to Mr Bogues after he fell into the water, but he was declared dead when he arrived at hospital.
The death was the second tragedy to affect the family this year. The body of Mr Bogues's son Conor (26) has not yet been recovered after his fishing boat sank off Ardglass in January.
In Dublin, a female garda was injured after she was trapped under a 30-foot wooden hoarding blown over by winds in north Dublin. Strong gales knocked down a barrier which was being used to block off a construction site just off the N32 Malahide Road at Coolock.
The garda was working on Operation Freeflow when the hoarding toppled over and trapped her legs. She was taken to Beaumont hospital. A Garda spokesman said she had suffered a serious leg injury.
A spokesman for the ESB said 15,000 homes were without power, mainly in the midlands, Athlone, Ballinasloe, in parts of Leinster and the west and in some parts of the southeast.
Crews worked into the night but could not be sure that power would be restored to all homes by today, a spokesman said.
In Waterford, two men were taken to hospital after being rescued from the sea at Newtown Cove by an Irish Coast Guard helicopter shortly after 3pm
It is understood the pair, understood to be Czech nationals, were swept from the swimming platform in high winds, as they were taking photographs of the waves. Rescue services estimated that waves swelled to approximately 3m in height.
In Galway, the city fire brigade service rescued two people from the rocks off Salthill promenade after they were swept out in a severe gust shortly after lunchtime, while a cyclist had a narrow escape on the Western Distributor Road when a speed limit road sign was uprooted. In Moycullen, local residents in a new housing estate called the fire brigade to assist with potential flooding, while the roof of the community centre was blown off.
Severe weather led to minor mudslides, power failures, floods, fallen trees and blocked roads in many parts of Kerry.
Some of the worst flooding happened at Crossmolina, Co Mayo, when the River Deel burst its banks and residents in the town were evacuated.
Several acres of farmland were flooded in Cavan and Monaghan and considerable damage was caused to farm buildings. Part of a new road scheme between Castleblayney and Clontibret was completely under water.
Met Éireann warned that rain early in the week could cause further flooding and that high winds could return at the end of the week.
Forecaster Dr Aidan Nulty said yesterday's storm was unusual for the time of year. "We usually have the big storms after Christmas, we have already had three or four in the last few weeks and this weekend's was the worst."
The country could expect heavy rain today with heavy showers tomorrow, he said.
