Photo: Seod13ie · CC0Few Irish towns get more rain than Knocknacarra: 1,336 mm a year
Midwinter brings lows of about 3.0°C. Summers stay cool: July afternoons here are cooler than in 96% of Irish towns. Warming shows here too: 0.2°C more than in 1981–2010, led by April. Garden planting can start around 22 April; autumn frost returns near 4 November.
Met Éireann 1991–2020 averages for the town’s own square kilometre.
A year in Knocknacarra at a glance
Each month’s typical high and low, in °C.
What stands out about Knocknacarra’s climate
Compared with Irish towns, with its place among towns and neighbourhoods of 2,500+ in County Galway beside it.
What a year in Knocknacarra feels like
Typical highs and lows by season and by month, from Met Éireann’s 1991–2020 averages.
41 frosts and 3 days of 25°C a year
Air frosts come mostly from October to April, most of all in March (about 9).
Air frosts by month
Average nights below 0°C
Counted from Athenry’s daily readings, 2010–2020, 22 km east of Knocknacarra: Met Éireann publishes these for its stations only.
About 1,336 mm of rain a year
December is the wettest month and April the driest. The wettest of 20 towns and neighbourhoods of 2,500+ in County Galway. The wettest month brings about 2.0 times the rain of the driest. Athenry records 1 mm or more on about 193 days a year, and 10 mm on about 39.
Rain by month
Millimetres
Heating a home in Knocknacarra
83% of a year’s heating need falls between October and April. Months averaging under 10°C: November to April.
Degree days add up how far each day’s mean temperature falls below 15.5°C over a year.
Living with Knocknacarra’s climate
What the averages mean for a garden, a free afternoon and a bad-weather day.
In half of years the last air frost at Athenry comes by 22 April and the first by 4 November: about 196 frost-free days in between.
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; Knocknacarra’s hazards page covers the risks.
Flood & hazards →Met Éireann’s nearest station: Athenry
Athenry is 22 km east of Knocknacarra, the nearest of the 25 synoptic stations where Met Éireann records the weather around the clock. The station stands 40 m above sea level; Knocknacarra’s centre, 26 m.
| Month | High | Low | Rain | Air frosts |
|---|---|---|---|---|
| January | 8.5°C | 2.5°C | 131 mm | 7.8 |
| February | 9.0°C | 2.3°C | 112 mm | 6.8 |
| March | 10.3°C | 2.2°C | 90 mm | 8.5 |
| April | 13.4°C | 4.1°C | 64 mm | 2.5 |
| May | 15.6°C | 6.7°C | 74 mm | 0.5 |
| June | 17.9°C | 9.5°C | 79 mm | 0.0 |
| July | 18.8°C | 11.2°C | 109 mm | 0.0 |
| August | 18.2°C | 10.7°C | 118 mm | 0.0 |
| September | 16.8°C | 9.1°C | 107 mm | 0.1 |
| October | 13.8°C | 6.3°C | 111 mm | 1.4 |
| November | 10.3°C | 3.5°C | 124 mm | 5.7 |
| December | 8.7°C | 2.6°C | 150 mm | 7.7 |
| Year | 13.4°C | 5.9°C | 1,268 mm | 41 |
The table is Athenry’s own record, averaged over 2010–2020 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 Knocknacarra itself; the frosts and degree days are this station’s.
How Knocknacarra 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 Galway.
Warmer than it used to be
Knocknacarra’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 1,336 mm, up 5% from 1,272 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.
Knocknacarra and its neighbours
Newcastle has the warmest July afternoons (19.5°C, 0.5°C warmer). Choose a measure to recolour the map; tap a town for its climate.
The towns next door, side by side
The nearest towns of 1,000+ within 19 km: a hill, a valley or the sea can make a real difference over a short distance.
| Town | July high | January low | Rain a year |
|---|---|---|---|
| Knocknacarra | 19.0°C | 3.0°C | 1,336 mm |
| Taylor's Hill 2.1 km | 19.1°C about the same | 3.0°C about the same | 1,307 mm |
| Salthill 2.2 km | 19.3°C about the same | 3.2°C about the same | 1,282 mm |
| Rahoon 2.3 km | 19.2°C about the same | 3.0°C about the same | 1,312 mm |
| Newcastle 2.9 km | 19.5°C 0.5°C warmer | 3.1°C about the same | 1,290 mm |
| Dangan 3.0 km | 19.1°C about the same | 3.0°C about the same | 1,322 mm |
| Bearna 3.5 km | 19.1°C about the same | 3.3°C about the same | 1,325 mm |
Each town’s colour is Met Éireann’s 1 km grid at its own centre, so towns a few kilometres apart can differ.
Knocknacarra 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 | 8.8°C | 3.0°C | 5.9°C | 132 mm |
| February | 9.2°C | 3.0°C | 6.1°C | 109 mm |
| March | 10.8°C | 3.8°C | 7.3°C | 100 mm |
| April | 13.1°C | 5.2°C | 9.2°C | 76 mm |
| May | 15.7°C | 7.6°C | 11.6°C | 80 mm |
| June | 17.8°C | 10.1°C | 13.9°C | 86 mm |
| July | 19.0°C | 12.0°C | 15.5°C | 101 mm |
| August | 18.9°C | 11.8°C | 15.3°C | 118 mm |
| September | 17.3°C | 10.1°C | 13.7°C | 108 mm |
| October | 14.2°C | 7.6°C | 10.9°C | 129 mm |
| November | 11.1°C | 5.1°C | 8.1°C | 145 mm |
| December | 9.1°C | 3.3°C | 6.2°C | 152 mm |
| Year | 13.8°C | 6.9°C | 10.3°C | 1,336 mm |
How much a month can swing
December swings the most: over 11 years its average ranged from −1.0°C (2010) to 8.1°C (2015). August is the most reliable, staying within 2.2°C.
Where Knocknacarra’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 Knocknacarra’s population centre (0.3 km away).
- Weather station: the nearest of Met Éireann’s 25 synoptic stations, Athenry, 22 km east, from Met Éireann’s station list.
- Frosts and degree days: Athenry’s daily readings from Met Éireann (clidata.met.ie), 2010–2020, 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 Knocknacarra’s climate
How warm does Knocknacarra get in summer?
July is the warmest month, with average highs of 19.0°C.
How cold does Knocknacarra get in winter?
The coldest nights come in January, averaging 3.0°C. At Athenry, the nearest Met Éireann station, the air drops below 0°C on about 41 nights a year (2010–2020).
How much rain does Knocknacarra get?
About 1,336 mm a year, more than 96% of Irish towns. December is the wettest month (152 mm) and April the driest (76 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 Knocknacarra itself. Its nearest synoptic station is Athenry.
Are these figures for Knocknacarra itself?
Partly. The temperatures and rain are Met Éireann’s 1991–2020 averages on its 1 km grid, read at Knocknacarra’s population centre; the frosts, degree days and year-to-year swings are those of Athenry, 22 km 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 Knocknacarra’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 Knocknacarra →
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).