Yesterday was the warmest day of the year so far, according to Met Éireann, with one weather station in Connacht reaching a temperature of 20.9C.
In a social media post last night, the forecaster said Mount Dillon in Co Roscommon saw the highest temperature.
It added that four other weather stations reached at least 20C yesterday. They include Shannon Airport in Co Clare, Belmullet in Co Mayo, Mace Head and Athenry in Co Galway.
The previous warmest day was 27 March, when Met Éireann reported 18.9C in Newport Furnace in Co Mayo.
Last year's highest temperature was also reported at Mount Dillon on 21 July, with a temperature of 30.8C.
Meanwhile this morning and afternoon will see a wet start to the week, with heavy showers in some places. Some showers will be heavy with the potential for localised thundery downpours.
Highest temperatures of 16C to 20C are forecast.
Rain will become widespread and heavy through tomorrow afternoon, especially in the east. Western parts will have more showery conditions, with some sunny spells. Some thundery downpours are likely in parts
The weather will remain unsettled for the rest of the week, with spells of rain and showers. Temperatures will return closer to average.
Today was the warmest day of the year so far!☀️😎— Met Éireann (@MetEireann) May 15, 2022
Mount Dillon in Co. Roscommon saw the mercury reach to 20.9°C🌡️ this afternoon, with several other stations across the west reaching 20+°C.
Keep up with our latest weather forecasts here⬇️https://t.co/yEsIuCkWlq pic.twitter.com/UtsWZCNJIc