Climate of Ireland

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Belmullet (1981-2010)
Climate chart (explanation)
JFMAMJJASOND
 
 
134
 
9
4
 
 
97
 
9
4
 
 
99
 
10
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72
 
12
6
 
 
70
 
15
8
 
 
72
 
16
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79
 
18
12
 
 
102
 
18
12
 
 
102
 
17
11
 
 
146
 
14
8
 
 
134
 
11
6
 
 
137
 
9
4
Average max. and min. temperatures in °C
Precipitation totals in mm
 
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A typical North Atlantic low-pressure area moving across Ireland

The climate of Ireland can be summed up as being mild, moist and changeable with abundant rainfall and a lack of temperature extremes. It is defined as a temperate oceanic climate, or Cfb on the Köppen climate classification system, a classification it shares with most of northwest Europe.[1] The country receives generally warm summers and mild winters, and is considerably warmer than other areas on its latitude. This is due to the fact it lies in the northeastern Atlantic Ocean, and as a result is warmed by the North Atlantic Current all year.

The influence of the North Atlantic Current also ensures the coastline of Ireland remains ice-free throughout the winter—unlike for example the Sea of Okhotsk and the Labrador Sea which are at a similar latitude. The climate in Ireland does not experience extreme weather, with tornadoes and similar weather features being rare.

Temperature[edit]

Ireland, as a whole, experiences a lack of temperature extremes compared to other areas of similar latitudes. Summers are generally warm and winters are mild. There is a regional variation, with inland areas being cooler in winter and warmer in Summer than their coastal counterparts.

The warmest areas are found along the south-west coast. Valentia Island, County Kerry has the highest annual mean temperature, at 10.4 °C (50.7 °F).[2]

The coldest areas are found inland. Clones, County Monaghan and Mullingar, County Westmeath both have the lowest annual mean temperature, at 8.8 °C (47.8 °F).[3][4]

The highest temperature ever recorded in Ireland was 33.3 °C (91.9 °F) at Kilkenny Castle, County Kilkenny on 26 June 1887. The lowest temperature was −19.1 °C (−2.4 °F) at Markree Castle, County Sligo on 16 January 1881.[5]

Extreme heat and cold are both rare throughout the country. Summer temperatures exceed 30 °C (86 °F) usually once or twice every decade (2013, 2006, 2005, 2003, 1995, 1990, 1989, 1983, 1976 and 1975 are recent examples), though commonly reach the high 20s °C (low 80s °F) most summers, while severe freezes occur only occasionally in winter, with temperatures below −10 °C (14 °F) being very uncommon, and temperatures below freezing uncommon in many coastal areas.

Mean daily winter temperatures vary from 4.0 °C (39.2 °F) to 7.6 °C (45.7 °F), and mean daily summer temperatures vary from 15 °C (59 °F) to 20 °C (68.0 °F).

Climate data for Ireland
MonthJanFebMarAprMayJunJulAugSepOctNovDecYear
Record high °C (°F)18.5
(65.3)
18.1
(64.6)
23.6
(74.5)
25.8
(78.4)
28.4
(83.1)
33.3
(91.9)
32.3
(90.1)
31.5
(88.7)
29.1
(84.4)
25.2
(77.4)
20.0
(68)
18.1
(64.6)
33.3
(91.9)
Record low °C (°F)−19.1
(−2.4)
−17.8
(0)
−17.2
(1)
−8.5
(16.7)
−6.5
(20.3)
−3.3
(26.1)
−1.1
(30)
−2.7
(27.1)
−3.2
(26.2)
−8.3
(17.1)
−11.5
(11.3)
−18.7
(−1.7)
−19.1
(−2.4)
Source: Met Éireann / Met Office

Hardiness zones[edit]

Ireland's (and Britain's) hardiness zones

Most of Ireland is in hardiness zone 9, with the interior being zone 8 and the south-west coast being in zone 10.

Frost[edit]

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.[6] Along the coast, air frost occurs less regularly. In the Sperrins and the Glens of Antrim air frost occurs around 80 days of year.[7] The pattern is similar with ground frost, with on average around 100 days of ground frost in the lowlands and over 140 in the mountains.[8]

Frost is rarer along the coast, in urban areas and also in western and southern areas.

Roches Point, County Cork receives the least number of days with air frost, with an average of 7.0 days with air frost recorded annually.[9]

Kilkenny, County Kilkenny receives the most amount of days with air frost, with an average of 53.0 days with air frost recorded annually.[10]

In Dublin, Dublin Airport records air frost on average 24.3 days per year, while Casement Aerodrome (which is further inland) records air frost on average 41.3 days per year.[11][12]

Sunshine[edit]

The sunniest months are May and June. During these months sunshine duration averages between 5 and 6½ hours per day over most of the country. The south-east gets the most sunshine, averaging over 7 hours a day in early summer. December is the dullest month with an average daily sunshine ranging from about 1 hour in the north to almost 2 hours in the south-east. Over the year as a whole most areas get an average of between 3¼ and 3¾ hours of sunshine each day. Irish skies are completely covered by cloud roughly half of the time.

The sunniest part of the island is the south-east coast. Rosslare, County Wexford is the sunniest area, and receives on average 4.38 hours of sunshine per day (1,598.41 hours per year).[13]

The dullest, i.e., least sunny, part of the island is generally in the west and northwest of the country. However, Birr, County Offaly, in the midlands, is the dullest station, receiving on average 3.2 hours of sunshine per day, considerably less than the stations at Malin Head in the North or Belmullet in the West.[15] Inland areas tend to receive less sunshine than coastal areas due to the convective development of clouds over land. Cloud develops because of vertical air currents caused by thermal heating of the ground.[16]

July sunshine in County Cavan

Precipitation[edit]

Rainfall[edit]

Flooded farmland in County Down

Rainfall is the most common form of precipitation on the island, and is extremely common throughout Ireland, although some parts of the west coast receive over four times as much rain as the east coast. Rainfall in Ireland normally comes from Atlantic frontal systems which travel north-east over the Island, bringing cloud and rain. Most of the eastern half of the country has between 750 and 1,000 mm (29.5 and 39.4 in) of rainfall in the year. Rainfall in the west generally averages between 1,000 and 1,250 mm (39.4 and 49.2 in). In many mountainous districts rainfall exceeds 3,000 mm (118.1 in) per year. The wettest months almost everywhere are December and January. April is the driest month generally, but in many southern parts June is the driest.

The average number of "wet days" (days with more than 1 mm (0.039 in) of rain) ranges from about 151 days a year along the east and south-east coasts, to about 225 days a year in parts of the west.

The wettest weather station is that in Valentia Island, County Kerry, which receives 1,430.1 mm (56.30 in) of rain per year, on average.[2]

The driest weather station is Casement Aerodrome, County Dublin, which receives 711.4 mm (28.01 in) of rain per year, on average.[12]

The weather station with the highest number of "wet days" is Belmullet, County Mayo with 193 days per year,[18] while the station with the lowest number of "wet days" is Dublin Airport, County Dublin with 128 days per year.[11]

Rainfall records[19][edit]

Snowfall[edit]

Snow in Wicklow

Severe cold weather is uncommon in Ireland with the majority of winter precipitation coming in the form of rain. Although hills and mountainous regions in the country can see up to 30 days of snowfall annually, most low lying regions of the island only see a few days of lying snow per year (from December to March inclusive), or may see no snow at all during some winters. However, in recent winters, there has been a significant increase in prolonged "cold snaps", in which heavy snow does fall across Ireland for several weeks, often causing disruption to traffic and services across Ireland. Consequently, there have been increased calls to prepare the country for snow and ice, including the distribution of grit, salt, and other snow-treatable minerals. In late 2011, the Irish Government set up "Winter-Ready", in order to prepare the country for such severe weather.[20]

Due to the volatility of Ireland's weather (which is mainly because of the influence of the Atlantic Ocean, Gulf Stream and North Atlantic Drift, as well as Ireland's Northerly latitude and vulnerability to Siberian/Arctic winds) weather during the Winter months is very variable and difficult to predict, with the aforementioned factors making both extremely low temperatures and relatively mild temperatures possible.

The snowiest weather station is that in Clones, County Monaghan; which receives, on average, nearly 30 days of snow and/or sleet per year. Of these, 10.8 days have snow lying at 09:00.[3]

The least snowy weather station is that in Valentia Island, County Kerry; which receives, on average, 5.6 days of snow and/or sleet per year. Of these, 0.8 days have snow lying at 09:00.[2]

Hail[edit]

Hail, like snow and sleet, is also rare in Ireland; however it can occur at any time of the year. It is most common in spring during thunderstorms.

Malin Head, County Donegal receives the most hail; with there being 48.4 days per year with hail falling.[21]

Roches Point, County Cork receives the least hail; with there being 8.0 days per year with hail falling.[22]

Thunderstorms[edit]

Thunderstorms are quite rare in Ireland, and are more likely to happen late in summer; though can occur at any time of the year.

Cork Airport, County Cork experiences the least thunder; receiving it 3.7 days per year on average.[23]

Valentia Island, County Kerry experiences the most thunder; receiving it 7.1 days per year on average.[2]

Wind[edit]

Generally, the coast tends to be windier than inland areas; and the west tends to be windier than the east.

The station with the highest mean wind speed is Malin Head, County Donegal; averaging at 16.3 kn (30.2 km/h; 18.8 mph). Malin Head also receives the most gale force winds, recording them on average 66.0 days per year.[21]

The station with the lowest mean wind speed is Kilkenny, County Kilkenny; averaging at 6.5 kn (12.0 km/h; 7.5 mph).[10]

The station that records the least amount of gale force winds is that in Birr, County Offaly; recording them on average 1.2 days per year.[24]

The highest wind speed ever recorded in Ireland was 327 km/h (203 mph; 177 kn) at Kilkeel, County Down on 12 January 1974.

Tornadoes are very rare in Ireland, with around less than ten reported every year - mostly in August.[25]

Fog[edit]

Fog in the Wicklow Mountains

Fog is more common inland and on higher altitudes; mainly during winter and during the morning at times of high pressure.

The foggiest station is that at Cork Airport, County Cork, which has 99.5 days of fog per year.[23]

The least foggy station is that at Valentia Island, County Kerry, which has 8.9 days of fog per year.[2]

Recent records[edit]

Rainfall[edit]

Rainfall records
Year2011201020092008200720062005
Highest annual total1,720 millimetres (68 in)
Valentia Observatory
1,332 millimetres (52.4 in)
Valentia Observatory
2,175 millimetres (85.6 in)
Valentia Observatory
1,673 millimetres (65.9 in)
Valentia Observatory
1,351 millimetres (53.2 in)
Valentia Observatory
1,761 millimetres (69.3 in)
Valentia Observatory
1,500 millimetres (59 in)
Valentia Observatory
Lowest annual total672 millimetres (26.5 in)
Dublin Airport
671 millimetres (26.4 in)
Dublin Airport
918 millimetres (36.1 in)
Dublin Airport
944 millimetres (37.2 in)
Dublin Airport
755 millimetres (29.7 in)
Rosslare
678 millimetres (26.7 in)
Casement Aerodrome
624 millimetres (24.6 in)
Casement Aerodrome
Highest daily rainfall106.6 millimetres (4.20 in)
Delphi Lodge
17 November
86.5 millimetres (3.41 in)
Knock Airport
6 September
51.2 millimetres (2.02 in)
Cork Airport
19 November
102.0 millimetres (4.02 in)
Belderrig
13 August
53.3 millimetres (2.10 in)
Phoenix Park
22 June
55.3 millimetres (2.18 in)
Valentia Observatory
25 October
66.3 millimetres (2.61 in)
Cork Airport
24 July
Source: Met Éireann / Met Office

Temperature[edit]

Temperature records
Year2011201020092008200720062005
Highest mean annual temperature11.0 °C (51.8 °F)
Valentia Observatory
10.1 °C (50.2 °F)
Valentia Observatory
11.1 °C (52.0 °F)
Valentia Observatory
11.1 °C (52.0 °F)
Valentia Observatory
11.7 °C (53.1 °F)
Valentia Observatory
11.4 °C (52.5 °F)
Valentia Observatory
and
Rosslare
11.4 °C (52.5 °F)
Valentia Observatory
Lowest mean annual temperature8.9 °C (48.0 °F)
Knock Airport
7.9 °C (46.2 °F)
Knock Airport
8.7 °C (47.7 °F)
Knock Airport
8.7 °C (47.7 °F)
Knock Airport
9.5 °C (49.1 °F)
Knock Airport
9.1 °C (48.4 °F)
Knock Airport
9.1 °C (48.4 °F)
Knock Airport
Highest temperature26.0 °C (78.8 °F)
Athy
3 June

and
Cavan
3 June
26.8 °C (80.2 °F)
Ardfert
23 May
28.6 °C (83.5 °F)
Galway
2 June
25.9 °C (78.6 °F)
Ardtarmon
28 July

and
Castlederg
28 July
26.9 °C (80.4 °F)
Ballyshannon
9 June
32.3 °C (90.1 °F)
Elphin
19 July
30.3 °C (86.5 °F)
Kildalton
12 July
Lowest temperature−9.8 °C (14.4 °F)
Katesbridge
20 January
−18.7 °C (−1.7 °F)
Castlederg
23 December
−10.0 °C (14.0 °F)
Mullingar
25 December
−8.8 °C (16.2 °F)
Katesbridge
18 February
−8.0 °C (17.6 °F)
Cavan
7 February
−8.6 °C (16.5 °F)
Straide
3 March
−5.6 °C (21.9 °F)
Casement Aerodrome
3 March
Source: Met Éireann / Met Office

Sunshine[edit]

Sunshine records
Year2011201020092008200720062005
Highest annual total1,548 hours
Dublin Airport
1,771 hours
Cork Airport
1,561 hours
Dublin Airport
1,512 hours
Dublin Airport
1,789 hours
Rosslare
1,710 hours
Rosslare
1,619 hours
Rosslare
Lowest annual total1,123 hours
Knock Airport
1,530 hours
Knock Airport
1,319 hours
Knock Airport
1,249 hours
Birr
1,330 hours
Knock Airport
1,304 hours
Knock Airport
1,147 hours
Birr
Highest daily sunshine15.9 hours
Casement Aerodrome
3 June
16.0 hours
Casement Aerodrome
20 June
16.0 hours
Casement Aerodrome
24 June
15.3 hours
Malin Head
26 May
15.6 hours
Knock Airport
4 June

and
Malin Head
6 June
15.8 hours
Malin Head
25 June
15.6 hours
Rosslare
11 July

and
Dublin Airport
11 July
Source: Met Éireann / Met Office

Visibility[edit]

Visibility is generally very good, because of the proximity of industry to the coast, allowing breezes to disperse any smog.[26] Mist and fog often occur, as well as coastal fog in the east,[27] but it is generally not long-lasting. However in winter, it can be slow to clear.[26]

Climate charts[edit]

Belmullet (1981-2010)
Climate chart (explanation)
JFMAMJJASOND
 
 
134
 
9
4
 
 
97
 
9
4
 
 
99
 
10
5
 
 
72
 
12
6
 
 
70
 
15
8
 
 
72
 
16
10
 
 
79
 
18
12
 
 
102
 
18
12
 
 
102
 
17
11
 
 
146
 
14
8
 
 
134
 
11
6
 
 
137
 
9
4
Average max. and min. temperatures in °C
Precipitation totals in mm
Birr (1979-2008)
Climate chart (explanation)
JFMAMJJASOND
 
 
79
 
8
2
 
 
59
 
9
2
 
 
67
 
10
3
 
 
55
 
13
4
 
 
60
 
16
7
 
 
67
 
18
10
 
 
59
 
20
12
 
 
82
 
19
11
 
 
66
 
17
9
 
 
94
 
14
7
 
 
75
 
10
4
 
 
84
 
9
3
Average max. and min. temperatures in °C
Precipitation totals in mm
Casement Aerodrome (1981-2010)
Climate chart (explanation)
JFMAMJJASOND
 
 
64
 
8
2
 
 
49
 
8
2
 
 
51
 
10
3
 
 
52
 
12
4
 
 
59
 
15
7
 
 
63
 
18
9
 
 
54
 
20
12
 
 
72
 
20
11
 
 
60
 
17
10
 
 
82
 
14
7
 
 
74
 
10
4
 
 
76
 
8
2
Average max. and min. temperatures in °C
Precipitation totals in mm
Clones (1978-2007)
Climate chart (explanation)
JFMAMJJASOND
 
 
88
 
7
2
 
 
71
 
8
2
 
 
84
 
10
3
 
 
62
 
12
4
 
 
63
 
15
7
 
 
71
 
17
10
 
 
71
 
19
11
 
 
89
 
19
11
 
 
76
 
17
9
 
 
103
 
13
7
 
 
85
 
10
4
 
 
98
 
8
2
Average max. and min. temperatures in °C
Precipitation totals in mm
Cork Airport (1981-2010)
Climate chart (explanation)
JFMAMJJASOND
 
 
131
 
8
3
 
 
98
 
8
3
 
 
98
 
10
4
 
 
77
 
12
5
 
 
82
 
14
7
 
 
81
 
17
10
 
 
79
 
19
12
 
 
97
 
19
12
 
 
95
 
17
10
 
 
138
 
13
8
 
 
120
 
10
5
 
 
133
 
9
4
Average max. and min. temperatures in °C
Precipitation totals in mm
Dublin Airport (1981-2010)
Climate chart (explanation)
JFMAMJJASOND
 
 
63
 
8
2
 
 
49
 
8
2
 
 
53
 
10
3
 
 
54
 
12
5
 
 
60
 
15
7
 
 
67
 
18
10
 
 
56
 
20
12
 
 
73
 
19
12
 
 
60
 
17
10
 
 
79
 
14
7
 
 
73
 
10
5
 
 
73
 
8
3
Average max. and min. temperatures in °C
Precipitation totals in mm
Kilkenny (1978-2007)
Climate chart (explanation)
JFMAMJJASOND
 
 
78
 
8
2
 
 
66
 
9
2
 
 
68
 
11
3
 
 
56
 
13
4
 
 
60
 
16
7
 
 
61
 
18
9
 
 
55
 
20
11
 
 
78
 
20
11
 
 
69
 
18
9
 
 
95
 
14
7
 
 
80
 
11
4
 
 
90
 
9
2
Average max. and min. temperatures in °C
Precipitation totals in mm
Malin Head (1981-2010)
Climate chart (explanation)
JFMAMJJASOND
 
 
117
 
8
4
 
 
85
 
8
4
 
 
86
 
9
4
 
 
63
 
11
6
 
 
57
 
13
8
 
 
69
 
15
10
 
 
77
 
17
12
 
 
93
 
17
12
 
 
92
 
16
11
 
 
118
 
13
9
 
 
105
 
10
6
 
 
114
 
9
4
Average max. and min. temperatures in °C
Precipitation totals in mm
Mullingar (1979-2008)
Climate chart (explanation)
JFMAMJJASOND
 
 
92
 
7
2
 
 
72
 
8
2
 
 
78
 
10
3
 
 
62
 
12
4
 
 
69
 
15
6
 
 
71
 
17
9
 
 
62
 
19
11
 
 
81
 
19
11
 
 
74
 
17
9
 
 
102
 
13
6
 
 
82
 
10
4
 
 
97
 
8
2
Average max. and min. temperatures in °C
Precipitation totals in mm
Rosslare (1978-2007)
Climate chart (explanation)
JFMAMJJASOND
 
 
88
 
9
4
 
 
71
 
9
4
 
 
69
 
10
5
 
 
59
 
11
6
 
 
56
 
14
9
 
 
55
 
16
11
 
 
50
 
18
13
 
 
72
 
19
13
 
 
75
 
17
12
 
 
109
 
14
9
 
 
101
 
11
7
 
 
101
 
10
5
Average max. and min. temperatures in °C
Precipitation totals in mm
Shannon Airport (1981-2010)
Climate chart (explanation)
JFMAMJJASOND
 
 
102
 
9
3
 
 
76
 
9
3
 
 
79
 
11
5
 
 
59
 
13
6
 
 
65
 
16
8
 
 
70
 
18
11
 
 
66
 
20
13
 
 
82
 
20
13
 
 
76
 
18
11
 
 
105
 
14
8
 
 
94
 
11
6
 
 
104
 
9
4
Average max. and min. temperatures in °C
Precipitation totals in mm
Valentia Island (1981-2010)
Climate chart (explanation)
JFMAMJJASOND
 
 
174
 
10
5
 
 
124
 
10
5
 
 
124
 
11
5
 
 
97
 
13
6
 
 
94
 
15
8
 
 
95
 
17
11
 
 
99
 
18
13
 
 
115
 
18
13
 
 
125
 
17
11
 
 
177
 
14
9
 
 
169
 
12
7
 
 
165
 
10
5
Average max. and min. temperatures in °C
Precipitation totals in mm

Annalistic references[edit]

See Annals of Inisfallen (AI)

See also[edit]

References[edit]

  1. ^ Peel, M. C. and Finlayson, B. L. and McMahon, T. A. (2007). "Updated world map of the Köppen–Geiger climate classification". Hydrol. Earth Syst. Sci. 11: 1633–1644. doi:10.5194/hess-11-1633-2007. ISSN 1027-5606.  (direct: Final Revised Paper)
  2. ^ a b c d e Met Éireann - Valentia Observatory (30 Year Averages)
  3. ^ a b Met Éireann - Clones (30 Year Averages)
  4. ^ Met Éireann - Mullingar (30 Year Averages)
  5. ^ Met Éireann - Temperature
  6. ^ "N Ireland 1971-2000 averages". Meteorological Office. Retrieved 2008-05-17. 
  7. ^ "Days of Air Frost 1971-2000". Meteorological Office. Retrieved 2008-05-18. 
  8. ^ "Days of Ground Frost 1971-2000". Meteorological Office. Retrieved 2008-05-18. 
  9. ^ Met Éireann - Roches Point (30 Year Averages)
  10. ^ a b Met Éireann - Kilkenny (30 Year Averages)
  11. ^ a b Met Éireann - Dublin Airport (30 Year Averages)
  12. ^ a b Met Éireann - Casement Aerodrome (30 Year Averages)
  13. ^ [1]
  14. ^ "Climatological Information for Rosslare, Ireland". European Climate Assessment & Dataset. 
  15. ^ [2]
  16. ^ [3]
  17. ^ "Climatological Information for Birr, Ireland". European Climate Assessment & Dataset. 
  18. ^ Met Éireann - Belmullet (30 Year Averages)
  19. ^ http://www.met.ie/climate-ireland/weather-extremes.asp
  20. ^ "News". Shatter launches Winter Ready campaign. Irish Government News Service. Retrieved 1 December 2011. 
  21. ^ a b Met Éireann - Malin Head (30 Year Averages)
  22. ^ Met Éireann - Roche's Point (30 Year Averages)
  23. ^ a b Met Éireann - Cork Airport (30 Year Averages)
  24. ^ Met Éireann - Birr (30 Year Averages)
  25. ^ BreakingNews.ie - Yesterday’s tornados ‘almost unheard of’
  26. ^ a b "Met Office:Northern Ireland climate". Meteorological Office. Retrieved 2008-05-17. 
  27. ^ "Northern Ireland: Climate". Encyclopædia Britannica. Retrieved 2008-05-17. 

External links[edit]