Castletownbere has some of the mildest winter nights among Irish towns
The warmest part of a July day comes in at 18.7°C on average. Wet weather is most frequent in December and least in May. Rain is plentiful here, more than falls on almost every Irish town. Radiators earn their keep from November to March, the months that average under 10°C.
Met Éireann 1991–2020 averages for the town’s own square kilometre.
A year in Castletownbere at a glance
Each month’s typical high and low, in °C.
What stands out about Castletownbere’s climate
Compared with Irish towns, with its place among towns and neighbourhoods of 2,500+ in County Cork beside it.
What a year in Castletownbere feels like
Typical highs and lows by season and by month, from Met Éireann’s 1991–2020 averages.
About 4 air frosts a year
Ground frosts, when the grass drops below 0°C, come on about 25 nights a year. Air frosts come mostly from December, most of all in December (about 1).
Air frosts by month
Average nights below 0°C
Ground frosts by month
Average nights with the grass below 0°C
Counted from Sherkin Island’s daily readings, 2004–2020, 39 km south-east of Castletownbere: Met Éireann publishes these for its stations only. At that distance, read them as the area’s climate.
About 1,761 mm of rain a year
December is the wettest month and May the driest. The wettest of 55 towns and neighbourhoods of 2,500+ in County Cork. The wettest month brings about 2.0 times the rain of the driest. Sherkin Island records 1 mm or more on about 164 days a year, and 10 mm on about 32.
Rain by month
Millimetres
Heating a home in Castletownbere
84% of a year’s heating need falls between October and April. Months averaging under 10°C: November to March.
Degree days add up how far each day’s mean temperature falls below 15.5°C over a year.
Living with Castletownbere’s climate
What the averages mean for a garden, a free afternoon and a bad-weather day.
Frost comes in about 56% of winters at Sherkin Island, so tender plants can often stay out through winter.
Highs of 17–27°C with lows of 8°C or more: Jun, Jul, Aug and Sep.
Parks & trails →Averages smooth over storms, floods and heatwaves; Castletownbere’s hazards page covers the risks.
Flood & hazards →Met Éireann’s nearest station: Sherkin Island
Sherkin Island is 39 km south-east of Castletownbere, the nearest of the 25 synoptic stations where Met Éireann records the weather around the clock. The station stands 21 m above sea level; Castletownbere’s centre, 15 m.
| Month | High | Low | Rain | Air frosts |
|---|---|---|---|---|
| January | 9.8°C | 5.8°C | 123 mm | 0.9 |
| February | 9.5°C | 5.3°C | 81 mm | 0.9 |
| March | 10.2°C | 5.5°C | 82 mm | 0.8 |
| April | 12.1°C | 6.9°C | 64 mm | 0.1 |
| May | 13.9°C | 9.0°C | 66 mm | 0.0 |
| June | 16.5°C | 11.4°C | 73 mm | 0.0 |
| July | 17.7°C | 12.8°C | 86 mm | 0.0 |
| August | 17.5°C | 12.8°C | 90 mm | 0.0 |
| September | 16.5°C | 11.8°C | 89 mm | 0.0 |
| October | 14.3°C | 10.1°C | 106 mm | 0.0 |
| November | 11.6°C | 7.4°C | 109 mm | 0.2 |
| December | 10.3°C | 6.4°C | 127 mm | 1.1 |
| Year | 13.3°C | 8.8°C | 1,095 mm | 4 |
The table is Sherkin Island’s own record, averaged over 2004–2020 from its daily readings (ours, not a Met Éireann table). The temperatures and rain elsewhere on this page are Met Éireann’s 1 km grid at Castletownbere itself; the frosts and degree days are this station’s.
How Castletownbere compares
Against the 321 Irish towns and city neighbourhoods of 2,500 or more, each read from Met Éireann’s grid at its own centre, and its place among towns and neighbourhoods of 2,500+ in County Cork.
Warmer than it used to be
Castletownbere’s 1991–2020 average is 0.2°C warmer than 1981–2010’s. The biggest change is in April (+0.4°C).
A year’s rain is 1,761 mm, up 4% from 1,692 mm.
Change by month
The two periods share 1991–2010, so the gap is a decade’s step, not the change between two separate 30-year periods.
Castletownbere weather by month
Average daily high and low, mean temperature and rain, 1991–2020, for the town itself (Met Éireann’s 1 km grid).
| Month | High | Low | Mean | Rain |
|---|---|---|---|---|
| January | 10.1°C | 5.3°C | 7.7°C | 185 mm |
| February | 10.3°C | 5.2°C | 7.8°C | 150 mm |
| March | 11.3°C | 5.7°C | 8.5°C | 128 mm |
| April | 13.2°C | 6.8°C | 10.0°C | 115 mm |
| May | 15.3°C | 8.9°C | 12.1°C | 103 mm |
| June | 17.4°C | 11.2°C | 14.3°C | 109 mm |
| July | 18.7°C | 12.8°C | 15.8°C | 132 mm |
| August | 18.8°C | 13.0°C | 15.9°C | 128 mm |
| September | 17.6°C | 11.9°C | 14.7°C | 136 mm |
| October | 14.8°C | 9.8°C | 12.3°C | 172 mm |
| November | 12.1°C | 7.4°C | 9.7°C | 199 mm |
| December | 10.7°C | 6.0°C | 8.3°C | 203 mm |
| Year | 14.2°C | 8.7°C | 11.4°C | 1,761 mm |
How much a month can swing
December swings the most: over 17 years its average ranged from 4.0°C (2010) to 10.3°C (2015). August is the most reliable, staying within 1.7°C.
Where Castletownbere’s numbers come from
Averages over 30 years, not a forecast: the town’s own from Met Éireann’s grid, the frosts and degree days from its nearest station.
- Temperature and rain: Met Éireann’s 1991–2020 averages on its 1 km grid (Climatological Notes 22 and 23), read at the grid point nearest Castletownbere’s population centre (0.8 km away).
- Weather station: the nearest of Met Éireann’s 25 synoptic stations, Sherkin Island, 39 km south-east, from Met Éireann’s station list.
- Frosts and degree days: Sherkin Island’s daily readings from Met Éireann (clidata.met.ie), 2004–2020, averaged by month: a month counts when 27 or more of its days were read (rain and sunshine: every day), and a figure needs 10 such years.
- Then and now: Met Éireann’s 1981–2010 averages on the same 1 km grid, at the same point.
- Altitudes: the town’s ground from the Copernicus GLO-30 surface model (a few metres high in built-up places), the station’s from Met Éireann.
- Comparisons: every Irish town and city neighbourhood of 2,500 or more, read the same way; the five city totals are left out.
- Not on this page: sunshine at this station, snow and wind. Met Éireann publishes none of them on a grid; the frosts here are its nearest station’s, not the town’s own.
Met Éireann 30-year averages · Met Éireann open data. Under Creative Commons Attribution 4.0 (CC BY 4.0).
Questions about Castletownbere’s climate
How warm does Castletownbere get in summer?
The warmest month is August, when afternoons average 18.8°C.
How cold does Castletownbere get in winter?
February nights average 5.2°C, the coldest of the year. At Sherkin Island, the nearest Met Éireann station, the air drops below 0°C on about 4 nights a year (2004–2020).
How much rain does Castletownbere get?
About 1,761 mm a year, more than almost every Irish town. December is the wettest month (203 mm) and May the driest (103 mm).
How sunny is it?
Met Éireann publishes its 1991–2020 sunshine averages for its weather stations only, not on the 1 km grid this page reads, so there is no sunshine figure for Castletownbere itself. Its nearest synoptic station is Sherkin Island.
Are these figures for Castletownbere itself?
Partly. The temperatures and rain are Met Éireann’s 1991–2020 averages on its 1 km grid, read at Castletownbere’s population centre; the frosts, degree days and year-to-year swings are those of Sherkin Island, 39 km south-east, the nearest of its synoptic stations.
Where do these figures come from?
Met Éireann’s 1991–2020 climate averages, published as maps of Ireland in 1 km squares (Climatological Notes 22 and 23); the page reads the square at Castletownbere’s population centre. They are 30-year averages, not a forecast.
Copyright Met Éireann. Source: www.met.ie. This data is published under a Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Met Éireann does not accept any liability whatsoever for any error or omission in the data, their availability, or for any loss or damage arising from their use. This material has been modified from the original: TownRatings reads the 1 km grid at each town’s population centre. Today’s forecast for Castletownbere →
Contains Central Statistics Office (CSO) data, Census 2022, and Tailte Éireann boundaries (CSO Urban Areas, Small Areas, local electoral areas, constituencies), under Creative Commons Attribution 4.0 (CC BY 4.0).