Climate of Ireland

The climate of Ireland is mild, humid and changeable with abundant rainfall and a lack of temperature extremes. Ireland's climate is defined as a temperate oceanic climate, or ''Cfb'' on the Köppen climate classification system, a classification it shares with most of northwest Europe. The island receives generally warm summers and cool winters.

As Ireland is downwind of a large ocean, it is considerably milder in winter than other locations at the same latitude, for example Newfoundland in Canada or Sakhalin in Russia. The Atlantic
overturning circulation, which includes ocean currents such as the North Atlantic Current and Gulf Stream, releases additional heat over the Atlantic, which is then carried by the prevailing winds towards Ireland giving, for example, Dublin a milder winter climate than other temperate oceanic climates in similar locations.

The prevailing wind blows from the southwest, breaking on the high mountains of the west coast. Rainfall is therefore a particularly prominent part of western Irish life, with Valentia Island, off the west coast of County Kerry, getting almost twice as much annual rainfall as Dublin on the east ( vs. ).

January and February are the coldest months of the year, and mean daily air temperatures fall between during these months. July and August are the warmest, with mean daily temperatures of , whilst mean daily maximums in July and August vary from near the coast, to inland. The sunniest months are May and June, with an average of five to seven hours sunshine per day. Though extreme weather events in Ireland are comparatively rare when compared with other countries in the European continent, they do occur. Atlantic depressions, occurring mainly in the months of December, January and February, can occasionally bring winds of up to to Western coastal counties, with the winter of 2013/14 being the stormiest on record. During the summer months, and particularly around late July/early August, thunderstorms can develop.

Temperature

Ireland experiences a lack of temperature extremes compared to other areas at similar latitudes. There is regional variation, with inland areas being cooler in winter and warmer in summer than their coastal counterparts.

The warmest areas are found along the southwest coast. Valentia Island has the highest average temperature, at 10.9 °C.

The coldest areas are found inland. Mullingar has the lowest average temperature, at 9.3 °C.

The highest temperature ever recorded in Ireland was 33.3 °C at Kilkenny Castle, on 26 June 1887. The lowest temperature was -19.1 °C at Markree Castle on 16 January 1881.

Six of the warmest ten years in Ireland have occurred since 1990. Due to climate change, it is estimated that the temperatures will rise everywhere by up to 3.4 degrees by the end of the century.

Extreme heat and cold are both rare throughout the country. Summer temperatures exceeding 30 °C are rare, usually only occurring every few years (2022, 2021, 2018, 2016, 2013, 2006, 2005, 2003, 1995, 1990, 1989, 1983, 1976 and 1975 are recent examples), although they commonly reach the high 20s most summers. Severe freezes occur only occasionally in winter, with temperatures below -10 °C being very uncommon in the lowlands and temperatures below freezing uncommon in many coastal areas. However, temperatures in the Wicklow Mountains are said to reach -10 °C annually.

Frost

Air frost occurs frequently in the winter, with most areas seeing over 40 days of air frost every year. In northern areas, air frost occurs on average 10.2 days every January, the month in which air frost occurs most frequently. In the Sperrins and the Glens of Antrim