Letterkenny in Summer
In summer (June, July and August), Letterkenny sees average daytime highs around 17°C and overnight lows near 11°C, with 298 mm of rain over about 52 wet days across the season. It is the warmest season of the year and the 3rd-wettest season.
Across summer, daytime highs hold fairly steady around 17°C. The sky is clear or mostly clear about 4% of the time across summer, and the air most often feels dry.
Summer is Letterkenny's best season of the year to visit on our travel score. For the whole year in context, see Letterkenny's year-round climate.
- Avg daytime high
- 17°C
- warmest season of the year
- Avg overnight low
- 11°C
- Rainfall
- 298 mm
- 52 wet days
- Avg wind
- 14 km/h
- Travel score
- 4.2
- best season of the year
- Months
- Jun · Jul · Aug
Temperature in Letterkenny in Summer
Across summer, daytime highs hold fairly steady around 17°C.
A typical summer day in Letterkenny reaches about 17°C and drops to 11°C overnight. The warmest of the three months is July, the coolest June.
How summer really feels in Letterkenny
Once humidity and wind are folded in, summer brings about 0 days that feel above 32°C and 0 that feel at or below 0°C.
summer sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.
Letterkenny weather by month
How the three summer months (June, July and August) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 7° / 3° | 108 | 18.5 | 2 | 7.6 | 0.8 |
| Feb | 8° / 3° | 91 | 15.9 | 1.8 | 9.3 | 1.0 |
| Mar | 9° / 4° | 88 | 17 | 1.3 | 11.4 | 1.5 |
| Apr | 11° / 5° | 80 | 16.1 | 0.3 | 13.8 | 2.3 |
| May | 14° / 7° | 86 | 15.9 | 0 | 15.8 | 3.3 |
| Jun | 16° / 10° | 92 | 16 | 0 | 17 | 3.9 |
| Jul | 17° / 12° | 101 | 18 | 0 | 16.5 | 4.3 |
| Aug | 17° / 12° | 105 | 17.8 | 0 | 14.7 | 4.3 |
| Sep | 15° / 10° | 88 | 15.5 | 0 | 12.5 | 3.9 |
| Oct | 13° / 8° | 105 | 17.1 | 0 | 10.2 | 2.8 |
| Nov | 10° / 6° | 110 | 18.8 | 0.3 | 8.1 | 1.6 |
| Dec | 8° / 4° | 113 | 18.1 | 1.2 | 7 | 0.9 |
Cloud cover in Summer
The sky is clear or mostly clear about 4% of the time across summer.
Chance of precipitation in Summer
Letterkenny gets around 298 mm of rain over 52 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Summer
Winds average 14 km/h across summer.
Sunrise & sunset in Summer
Daylight runs from about 16 h 36 min in early June to 13 h 42 min by late August. The lit band spans sunrise to sunset each day.
Solar energy in Summer
Average shortwave solar energy reaching the ground each day across summer, about 4.2 kWh/m².
Is summer a good time to visit Letterkenny?
Our two travel scores rate summer for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
summer is a reasonable time to visit Letterkenny for sightseeing.
What to pack for Letterkenny in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, Letterkenny sees daytime highs around 17°C and nights near 11°C. Pack rain gear. Worth having: a warm layer and sun protection. About 52 days see rain.
Sea temperature near Letterkenny in Summer
The nearest coast averages about 14°C across summer — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 45 km away) is warmest in August at about 15°C and coldest in February near 9°C.
The water stays below 20°C all year — cool enough that most swimmers want a wetsuit.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 9 | 9 | 9 | 9 | 11 | 13 | 15 | 15 | 15 | 13 | 12 | 10 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Cool | Bracing | Bracing | Bracing | Bracing |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 9 | Bracing |
| Feb | 9 | Bracing |
| Mar | 9 | Bracing |
| Apr | 9 | Bracing |
| May | 11 | Bracing |
| Jun | 13 | Bracing |
| Jul | 15 | Bracing |
| Aug | 15 | Cool |
| Sep | 15 | Bracing |
| Oct | 13 | Bracing |
| Nov | 12 | Bracing |
| Dec | 10 | Bracing |
UV index in Letterkenny in Summer
Clear-sky midday UV across summer averages around 5 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Letterkenny peaks around May 24 at about 5 (high) — a little sun protection helps at midday. It bottoms out near January 1 at about 0 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 6 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 0 | 1 | 2 | 3 | 5 | 5 | 5 | 5 | 3 | 2 | 1 | 0 |
| Level | Low | Low | Moderate | Moderate | High | High | High | Moderate | Moderate | Low | Low | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 0 | Low |
| Feb | 1 | Low |
| Mar | 2 | Moderate |
| Apr | 3 | Moderate |
| May | 5 | High |
| Jun | 5 | High |
| Jul | 5 | High |
| Aug | 5 | Moderate |
| Sep | 3 | Moderate |
| Oct | 2 | Low |
| Nov | 1 | Low |
| Dec | 0 | Low |
Where is Letterkenny?
Letterkenny sits at 55.0°N, 7.7°W, 8 m above sea level, in Ireland. The nearest listed city is Londonderry County Borough, 28 km away.
Topography around Letterkenny
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Letterkenny.
Within 3 km, the terrain around Letterkenny has only modest variations in elevation — a maximum elevation change of 199 m around an average of 73 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 452 m; within 80 km, large variations in elevation — a maximum elevation change of 706 m.
The land around Letterkenny is covered by grassland (60%) and trees (25%) within 3 km, grassland (72%) and trees (20%) within 16 km, and grassland (53%) and water (38%) within 80 km.
Ireland travel facts
- Travel advisory
- Level 1
- Exercise Normal Precautions
- Power plugs
- Type G
- 230 V · 50 Hz
- Prices
- ≈ 85% of US
- price level, 2025
- GDP per capita
- $131,592
- 2025
- Happiness
- 6.9 / 10
- World Happiness, 2025
- Safe drinking water
- 96%
- of population, 2024
- Homicide rate
- 0.7
- per 100k, 2023
- Road deaths
- 3.1
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Letterkenny (54.95°, -7.7333°, elevation 8 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.