Met Éireann has produced a new, more recent set of climate averages for Ireland.
The averages will be used from now on for day-to-day weather comparisons.
The data shows that Ireland's climate was half a degree warmer over the more recent 30-year period compared with the previous period.
Met Éireann said it was a significant rise in temperature.
Up until now the period 1961-1990 had been used to tell if the weather is wetter or warmer than average.
From now on, the period 1981 to 2010 will be used.
The data also shows a 5% increase in annual average rainfall, but conclusions cannot be drawn from that because of variability in weather.
It found Dublin to be one of the driest parts of the country, the west is the wettest, and the southeast is the sunniest.
Met Éireann says the data will be useful to planners involved in agriculture, infrastructure and water supplies.