Index


Introduction



The island of Ireland has an oceanic climate, cool and damp, cloudy and rainy throughout the year. Both the diurnal and the annual temperature ranges are narrow, so both the summer heat and the winter frost are rare.
Temperatures do not vary much in the island; however, the western coasts are milder in winter and cooler in summer. The southwest coast is particularly mild in winter.
In Ireland, Atlantic weather fronts move relentlessly one after another over the country, resulting in a rapid succession of cloudiness and sunshine, rain showers and subsequent improvements. Days with completely clear skies are rare: the weather is more likely to be variable or unstable, and in the interludes between disturbances you can expect, rather than clear skies, cloud running in the sky.

The wind in Ireland is frequent and lively, although it is generally stronger between late autumn and early spring. The windiest area is the northern one, which is literally windswept; the (relatively) least windy area is the inland south-eastern one (see Thurles, Kilkenny).

Rainfall is frequent throughout the island, but especially along the west coast, where it rains on average even more than once every two days; rainfall is more abundant on the slopes of the western hills, where it exceeds 2,000 millimeters (80 inches) per year. In Galway, on the west coast, 1,150 mm (45.5 in) of rain fall per year; in Cork, on the south coast, 1,200 mm (48 in). The least rainy area is the eastern one, where Dublin is located: here the rainfall is around 760 mm (30 in) per year.

Winter, from December to February, is quite cold but not freezing. The sky is often cloudy, the rains are frequent, and the most intense low pressure systems can cause wind storms. Temperatures are slightly above freezing during the night, while during the day they range from 7/8 °C (45/46 °F) in inland areas, to 8/10 °C (46/50 °F) along the coasts.
On milder periods, when southerly air masses reach Ireland, the temperature can reach 15 °C (59 °F) even in winter.
Cold waves are rare, and are usually short-lived because after a while the westerlies start to blow again. Snow is quite rare as well: on average, it falls for a few days in a year, and may not occur for an entire winter. Night temperatures drop below freezing (0 °C or 32 °F), usually by a few degrees, for about twenty days each year in Dublin, but only in the coldest winters they can drop to about -10 °C (14 °F). In most cases, on clear nights there can be light frosts, and nothing more.
In Ireland, there are no major mountain ranges, however, in the hills south of Dublin (Wicklow Mountains) and more rarely in the western highlands, with reach about a thousand meters (3,300 feet) in height, during winter the rain can turn into snow above 400/500 meters (1,300/1,600 feet).

Spring, from March to May, is initially cold, and remains very cool or cold still in April, and sometimes in May; usually the temperature becomes quite mild only by the second half of May, when, however, nights can still be quite cold. In return, spring is the (relatively) least rainy season and the sunniest of the year.

In Summer, from June to August, temperatures are cool: average highs are around 17/18 °C (63/64 °F) in Ulster and northern areas, and around 18/19 °C (64/66 °F) in the rest of Ireland. The temperature rarely exceeds 25 °C (77 °F), and this happens only in the rare and short periods when the Azores High moves over the country, while it almost never reaches 30 °C (86 °F).

Autumn, from September to November, is cloudy and rainy, at times windy, with little room for sunshine.

Ireland

Malin Head

The northern coast, mild enough but windy in winter, is the coolest part of Ireland in summer. In Malin Head, the northernmost point of the island, in County Donegal, the average temperature in January and February is 6 °C (42.5 °F), while in July and August it's 14.5 °C (58.5 °F).
Malin Head - Average temperatures
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)4446810121211864
Max (°C)88911131517171613109
Min (°F)393939434650545452464339
Max (°F)464648525559636361555048

In Malin Head, the rains are not very abundant, around 1,000 mm (40 inches) per year, but they are frequent all year round. However, the least rainy season is spring.
Malin Head - Average precipitation
MonthJanFebMarAprMayJunJulAugSepOctNovDecYear
Prec.(mm)1006560555570958010010095105980
Prec.(in)3.92.62.42.22.22.83.73.13.93.93.74.138.6
Days181512131113141416171719179

Dublin

Here are the average temperatures of Dublin, the capital city, located on the east coast, which in summer is the warmest (or less cool) area of the country.
Dublin - Average temperatures
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)2235710121210753
Max (°C)881012151820191714108
Min (°F)363637414550545450454137
Max (°F)464650545964686663575046

As mentioned, the Dublin area is also the least rainy of the island, although the rains are quite frequent all year round. Here is the average precipitation.
Dublin - Average precipitation
MonthJanFebMarAprMayJunJulAugSepOctNovDecYear
Prec.(mm)655055556065557560807575760
Prec.(in)2.622.22.22.42.62.232.43.13329.9
Days131011111110111210121213135

The sky in Ireland is often cloudy, so the sun is rarely seen; however, the sunniest month (compared to the length of the days) is May. Here are the average daily sunshine hours in Dublin.
Dublin - Sunshine
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Hours234566554322

The sea in Ireland is not inviting for swimming, in fact the water temperature does not go above 15/16 °C (59/61 °F) in July and August. Here is the sea temperature in Dublin.
Dublin - Sea temperature
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Temp (°C)98891013151615141210
Temp (°F)484646485055596159575450

Valentia

The south-west coast (see towns such as Waterville and Cahirciveen, in County Kerry) in winter is the mildest area of Ireland, with very rare frosts, so much so that even sub-tropical plant species can thrive. On the small island of Valentia, the average temperature is 7 °C (45 °F) in January and February, and 15.5 °C (60 °F) in July and August.
Valentia - Average temperatures
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)5556811131311975
Max (°C)101011131517181817141210
Min (°F)414141434652555552484541
Max (°F)505052555963646463575450

In Valentia, directly exposed to wet currents from the south-west, the rains are abundant, around 1,500 mm (61 in) per year.
Valentia - Average precipitation
MonthJanFebMarAprMayJunJulAugSepOctNovDecYear
Prec.(mm)1751251259595951001151251751701651555
Prec.(in)6.94.94.93.73.73.73.94.54.96.96.76.561.2
Days201617141312141516192018193

Best Time



The best time to visit Ireland is from mid-May to August: the rains are frequent, the air is often very cool (especially in May), it's better to bring a jacket and umbrella (or rather a raincoat as it often rains in the wind), but the days are long, and you can hope to see the sun peeking through the clouds. May and June are cooler than July and August, on the other hand, they are (relatively) sunnier, in addition, you can enjoy the nature in bloom.
In September, the temperatures are still acceptable, but the sky is often cloudy, and the days are shorter than in the previous months.

What to pack



In winter: bring warm clothes, such as a sweater, a coat, a raincoat.
In summer: bring clothes for spring and autumn, a jacket and a sweater, a raincoat or umbrella.