1990s was the warmest decade of 20th century


Ireland's climate is getting warmer and wetter, according to Met Eireann figures for the 20th century, with long-term weather stations showing a "sharp rise" in mean air temperatures during the 1990s.

Four of the 10 warmest years of the century were recorded since 1995, including 1997, the warmest on record at almost every meteorological service station.

This follows a global trend, with figures from the World Meteorological Organisation showing that the 1990s was the warmest decade of the century, which itself was the warmest century of the millennium.

Last year average air temperatures in Ireland were above normal for the sixth successive year. Varying from 9 Celsius at Connacht Airport to 11.4 Celsius at Shannon Airport, they were about a degree higher than the average for the 30-year period 1961-1990.

The lowest air temperature of the year (6.7 Celsius) was recorded at Clones on January 11th, while Kilkenny saw the lowest ground-level temperature (11.9 Celsius) on December 19th.

Rainfall totals varied considerably. While it was the driest year since 1975 at Rosslare, it was the second-wettest year of the century at Malin Head.

Sunshine totals were near or slightly above normal in eastern areas but well below normal in the west. Malin Head saw the highest daily sunshine total of 15.3 hours on July 26th.

The warmest month of the century was August 1995, when mean temperatures were around 18 degrees Celsius, four degrees above the average.

The highest temperature on record in Ireland, 33.3 Celsius at Kilkenny Castle in June 1887, was not exceeded this century, but values of over 32 Celsius were found in the summers of 1921, 1934, 1976 and 1983.

The coldest months of the century were February 1947 and January 1963. Lullymore, Co Kildare, experienced the century's lowest air temperature: 18.8 Celsius, recorded on January 2nd, 1979. It was just above the lowest temperature ever measured, 19.1 Celsius at Markree Castle, Co Sligo, in January 1881.

At the two long-term stations, Valentia Observatory and Malin Head, the last two decades were the wettest of the century. Elsewhere, however, there was little variation in rainfall levels.

The highest monthly total of 790mm was recorded at a mountain gauge in the Cummeragh Mountains, Co Kerry, in October 1996. Daily rainfalls of around 200mm were recorded in the east of the country on August 25th, 1986, during Hurricane Charlie. The largest daily total, of 243.5mm, was recorded at Cloone Lake, Co Kerry, on September 18th, 1993.

Over a shorter time-span, just over 75mm of rain was recorded in an hour in Mount Merrion, Dublin, during a thunderstorm on June 11th, 1963.

Annual sunshine totals show a downward trend, although the 1990s were a little sunnier than the 1980s. The first, second and sixth decades of the century were the sunniest on record. July 1955 proved the sunniest month: Valentia Observatory measured 308 hours, or almost 10 hours sunshine per day.

Among the highest winds of the century were 98 knots (113 m.p.h.), recorded on September 16th, 1961, at Malin Head during Hurricane Debbie. At inland stations, storm force 11 wind-speeds (over 55 knots) were recorded in the Dublin area in February 1903 and at Cork and Shannon Airports during the 1997 Christmas Eve storm.