Portarlington climate — normals and trends
Portarlington (Ireland) has a temperate oceanic climate (Cfb) under the Köppen-Geiger classification. Its mean annual temperature is 9.9 °C and it receives 808 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is July (15.6 °C on average) and the coldest is January (5.0 °C). Rainfall peaks in December.
Portarlington averages 26 frost days, 0 hot days (≥ 30 °C) and 152 rainy days per year.
Portarlington has warmed by +0.6 °C between 1940 and 2025, or +0.07 °C per decade. This trend is statistically significant.
The number of frost days there went from about 33 to 19 per year over the period.
The hottest day of the period reached 30.5 °C (on 29 June 1976) and the coldest -13.8 °C (on 12 January 1982).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
PortarlingtonLeinster
- coords
- 53.16°, -7.19°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
9.9°C
Average daily high
12.9°C
Average daily low
6.9°C
Annual rainfall
808mm
Sunshine / day
6.8h
Mean relative humidity
81%
Average peak wind
20.0km/h
Seasonal range
10.6°C
Frost days (< 0 °C)
26 d/yr
Hot days (≥ 30 °C)
0 d/yr
Rainy days (≥ 1 mm)
152 d/yr
Annual snowfall
9.8 cm
Average feels-like high
10.3 °C
Average feels-like low
4.0 °C
Average peak gust
41.9 km/h
Tropical nights (≥ 20 °C)
0 d/yr
Solar radiation
9.4 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+0.6 °C
since 1940
+0.1 °C per decade · r² = 0.12 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
30.5 °C
29 June 1976
Coldest day
-13.8 °C
12 January 1982
Wettest day
64 mm
25 August 1986
Windiest day
65.4 km/h
16 September 1961
Strongest gust
130.7 km/h
24 December 1999
Hottest feels-like
33.3 °C
29 July 1948
Coldest feels-like
-18.5 °C
12 January 1982
Snowiest day
27.2 cm
8 December 1954
Sunniest day
16.7 h
20 June 2022
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | 7.3 °C | -0.1 °C | 74 mm | +4 mm |
| Feb | 9.0 °C | +1.1 °C | 64 mm | +7 mm |
| Mar | 11.8 °C | +1.9 °C | 21 mm | -39 mm |
| Apr | 15.0 °C | +2.9 °C | 87 mm | +29 mm |
| May | 17.5 °C | +2.5 °C | 51 mm | -18 mm |
| Jun | 18.7 °C | +1.1 °C | 67 mm | +2 mm |
| Jul | 20.4 °C | +1.5 °C | 60 mm | -7 mm |
| Aug | 20.1 °C | +1.4 °C | 39 mm | -36 mm |
| Sep | 16.2 °C | -0.3 °C | 100 mm | +32 mm |
| Oct | 13.5 °C | +0.1 °C | 98 mm | +23 mm |
| Nov | 10.7 °C | +1.0 °C | 117 mm | +48 mm |
| Dec | 9.2 °C | +1.2 °C | 85 mm | +9 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Portarlington?
Portarlington has a temperate oceanic climate (Köppen Cfb). Over 1940-2025, the average annual temperature is 9.9 °C and it receives 808 mm of precipitation per year.
What is the hottest day ever recorded in Portarlington?
The hottest day measured in Portarlington between 1940 and 2025 was 29 June 1976, reaching 30.5 °C.
What is the coldest day in Portarlington?
The coldest day measured in Portarlington between 1940 and 2025 was 12 January 1982, at -13.8 °C.
Does it snow in Portarlington?
Yes. Portarlington gets on average 9.8 cm of snow per year and has around 26 frost days.
Has the climate of Portarlington warmed?
Yes: Portarlington warmed by +0.6 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Portarlington?
The wettest day measured in Portarlington between 1940 and 2025 was 25 August 1986, with 64 mm of rain in 24 hours.
What was the windiest day in Portarlington?
The windiest day measured in Portarlington between 1940 and 2025 was 16 September 1961, with winds reaching 65.4 km/h.
What is the warmest month in Portarlington?
The warmest month in Portarlington is July (15.6 °C on average); the coldest is January (5.0 °C).
How much does it rain in Portarlington?
Portarlington receives on average 808 mm of precipitation per year, spread over about 152 rainy days.
Is it sunny in Portarlington?
Portarlington gets on average 6.8 hours of sunshine per day, roughly 2,482 hours per year over 1940-2025.
What is the biggest single-day snowfall in Portarlington?
The heaviest 24-hour snowfall measured in Portarlington between 1940 and 2025 was 8 December 1954, with 27.2 cm.
Are there tropical nights in Portarlington?
Almost never: tropical nights (temperature staying above 20 °C) are virtually non-existent in Portarlington.
What was the most extreme apparent temperature in Portarlington?
In Portarlington, between 1940 and 2025, the highest apparent temperature reached 33.3 °C on 29 July 1948, and the lowest was -18.5 °C on 12 January 1982.
Compare Portarlington with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Portarlington