Dry weather: only 758 mm a year falls on Harmonstown, less than on 88% of Irish towns
Midwinter brings lows of about 3.1°C. November is the wettest month, February the driest. Summers stay cool: July afternoons here are cooler than in 67% of Irish towns. Seedlings are safe outdoors from about 20 April, with the first autumn frost due around 3 November.
Met Éireann 1991–2020 averages for the town’s own square kilometre.
A year in Harmonstown at a glance
Each month’s typical high and low, in °C.
What stands out about Harmonstown’s climate
Compared with Irish towns, with its place among towns and neighbourhoods of 2,500+ in County Dublin beside it.
What a year in Harmonstown feels like
Typical highs and lows by season and by month, from Met Éireann’s 1991–2020 averages.
About 35 air frosts a year
Ground frosts, when the grass drops below 0°C, come on about 87 nights a year. Air frosts come mostly from November to April, most of all in February (about 7).
Air frosts by month
Average nights below 0°C
Ground frosts by month
Average nights with the grass below 0°C
Counted from Dublin Airport’s daily readings, 1991–2020, 5.8 km north-west of Harmonstown: Met Éireann publishes these for its stations only.
About 758 mm of rain a year
November is the wettest month and February the driest. 77th wettest of 116 towns and neighbourhoods of 2,500+ in County Dublin. The wettest month brings about 1.6 times the rain of the driest. Dublin Airport records 1 mm or more on about 136 days a year, and 10 mm on about 18.
Rain by month
Millimetres
Sunshine by month
Hours, at Dublin Airport
Heating a home in Harmonstown
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 Harmonstown’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 Dublin Airport comes by 20 April and the first by 3 November: about 197 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; Harmonstown’s hazards page covers the risks.
Flood & hazards →Met Éireann’s nearest station: Dublin Airport
Dublin Airport is 5.8 km north-west of Harmonstown, the nearest of the 25 synoptic stations where Met Éireann records the weather around the clock. The station stands 71 m above sea level; Harmonstown’s centre, 30 m.
| Month | High | Low | Rain | Air frosts | Sun (hours) |
|---|---|---|---|---|---|
| January | 8.2°C | 2.4°C | 62 mm | 6.9 | 60 |
| February | 8.6°C | 2.2°C | 52 mm | 7.2 | 81 |
| March | 10.2°C | 2.7°C | 51 mm | 5.9 | 115 |
| April | 12.3°C | 3.9°C | 55 mm | 3.7 | 161 |
| May | 15.0°C | 6.3°C | 57 mm | 0.7 | 197 |
| June | 17.7°C | 8.9°C | 64 mm | 0.0 | 178 |
| July | 19.4°C | 11.0°C | 62 mm | 0.0 | 158 |
| August | 19.1°C | 10.8°C | 74 mm | 0.0 | 155 |
| September | 17.0°C | 9.0°C | 62 mm | 0.0 | 131 |
| October | 13.7°C | 6.7°C | 79 mm | 0.8 | 104 |
| November | 10.4°C | 4.3°C | 83 mm | 3.1 | 72 |
| December | 8.4°C | 2.7°C | 72 mm | 6.8 | 56 |
| Year | 13.3°C | 5.9°C | 772 mm | 35 | 1,468 |
The table is Dublin Airport’s own record, averaged over 1991–2020 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 Harmonstown itself; the frosts, sunshine and degree days are this station’s.
How Harmonstown 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 Dublin.
Warmer than it used to be
Harmonstown’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 758 mm, up 5% from 722 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.
Harmonstown and its neighbours
Every town next door is within half a degree of Harmonstown in January and July. 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 |
|---|---|---|---|
| Harmonstown | 19.7°C | 3.1°C | 758 mm |
| Edenmore 0.8 km | 19.7°C about the same | 3.2°C about the same | 751 mm |
| Ayrfield 1.5 km | 19.7°C about the same | 3.1°C about the same | 754 mm |
| Clontarf East 1.7 km | 19.9°C about the same | 3.2°C about the same | 750 mm |
| Beaumont 1.9 km | 19.8°C about the same | 2.9°C about the same | 770 mm |
| Darndale 2.0 km | 19.7°C about the same | 3.0°C about the same | 760 mm |
| Donaghmede 2.0 km | 19.7°C about the same | 3.3°C about the same | 742 mm |
Each town’s colour is Met Éireann’s 1 km grid at its own centre, so towns a few kilometres apart can differ.
Harmonstown 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 | 8.6°C | 3.1°C | 5.9°C | 60 mm |
| February | 9.0°C | 3.0°C | 6.0°C | 51 mm |
| March | 10.6°C | 3.9°C | 7.2°C | 52 mm |
| April | 12.6°C | 5.3°C | 9.0°C | 51 mm |
| May | 15.3°C | 7.7°C | 11.5°C | 55 mm |
| June | 18.0°C | 10.3°C | 14.1°C | 64 mm |
| July | 19.7°C | 12.2°C | 15.9°C | 61 mm |
| August | 19.5°C | 12.0°C | 15.8°C | 71 mm |
| September | 17.5°C | 10.3°C | 13.9°C | 63 mm |
| October | 14.2°C | 7.9°C | 11.1°C | 76 mm |
| November | 11.0°C | 5.2°C | 8.1°C | 83 mm |
| December | 8.9°C | 3.3°C | 6.1°C | 70 mm |
| Year | 13.8°C | 7.0°C | 10.4°C | 758 mm |
How much a month can swing
December swings the most: over 30 years its average ranged from −0.1°C (2010) to 8.6°C (2015). July is the most reliable, staying within 3.1°C.
Where Harmonstown’s numbers come from
Averages over 30 years, not a forecast: the town’s own from Met Éireann’s grid, the frosts, sunshine 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 Harmonstown’s population centre (0.5 km away).
- Weather station: the nearest of Met Éireann’s 25 synoptic stations, Dublin Airport, 5.8 km north-west, from Met Éireann’s station list.
- Frosts, sunshine, degree days: Dublin Airport’s daily readings from Met Éireann (clidata.met.ie), 1991–2020, 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: snow and wind. Met Éireann publishes neither on a grid; the frosts and sunshine 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 Harmonstown’s climate
How warm does Harmonstown get in summer?
The warmest month is July, when afternoons average 19.7°C.
How cold does Harmonstown get in winter?
February nights average 3.0°C, the coldest of the year. At Dublin Airport, the nearest Met Éireann station, the air drops below 0°C on about 35 nights a year (1991–2020).
How much rain does Harmonstown get?
About 758 mm a year, less than 88% of Irish towns. November is the wettest month (83 mm) and February the driest (51 mm).
How sunny is it?
Dublin Airport, 5.8 km north-west, averages about 1,468 hours of sunshine a year (1991–2020, from its daily record). Met Éireann publishes no sunshine figure for the town itself.
Are these figures for Harmonstown itself?
Partly. The temperatures and rain are Met Éireann’s 1991–2020 averages on its 1 km grid, read at Harmonstown’s population centre; the frosts, degree days and year-to-year swings are those of Dublin Airport, 5.8 km north-west, 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 Harmonstown’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 Harmonstown →
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).