Letterkenny weather in October

In October, Letterkenny sees average daytime highs of 13°C and overnight lows near 8°C, with 105 mm of rain across 17.1 wet days and about 10.2 hours of daylight. It is the 6th-warmest and 4th-wettest month of the year here.

Highs ease over the month, from about 14°C in the first days to 11°C by the end. The sky is clear or mostly clear about 5% of the time in October, and the air most often feels dry.

Daylight stretches from about 11 h 18 min at the start of October to 9 h 06 min by month's end. Set against the rest of the year, October is Letterkenny's 4th-clearest and 6th-windiest month. For the whole year in context, see Letterkenny's year-round climate.

Daytime high
13°
6th warmest
Overnight low
8th coldest
Rainfall
105 mm
17.1 wet days
Daylight
10 h 12 min
7:11 AM – 5:21 PM
Cloud cover
79%
4th clearest
Wind
17 km/h
6th windiest
Solar energy
1.46 kWh/m²
Travel score
2.8
out of 10

Letterkenny is town in County Donegal, Ireland.

Density
472/km²
people per km²

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in October

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 14°C in the first days to 11°C by the end.

A typical October day in Letterkenny reaches about 13°C in the afternoon and slips back to 8°C overnight — a 5°C spread between the day's warmth and the night's chill. On most days the high lands between 10°C and 15°C. Set against its neighbours, October runs about 3°C cooler than September and about 3°C warmer than November.

10°15°20°151015202531
Avg high (°C)Avg low (°C)
1149
2149
3149
4149
5149
6149
7149
8139
9138
10138
11138
12138
13138
14138
15138
16138
17128
18128
19128
20127
21127
22127
23127
24127
25127
26117
27117
28117
29117
30117
31117

How October really feels in Letterkenny

Once humidity and wind are folded in, October averages 0 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
0
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

October 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 October compares with the rest of the year at a glance. October is the 6th-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 10818.527.60.8
Feb / 9115.91.89.31.0
Mar / 88171.311.41.5
Apr11° / 8016.10.313.82.3
May14° / 8615.9015.83.3
Jun16° / 10°92160173.9
Jul17° / 12°10118016.54.3
Aug17° / 12°10517.8014.74.3
Sep15° / 10°8815.5012.53.9
Oct13° / 10517.1010.22.8
Nov10° / 11018.80.38.11.6
Dec / 11318.11.270.9

Cloud cover in October

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 5% of the time in October.

Beyond those clear spells, partly cloudy skies cover about 15% of October, with mostly cloudy or overcast conditions the remaining 80%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
11882
21882
31981
41981
51981
61981
72080
82179
92179
102179
112278
122278
132278
142278
152278
162278
172278
182278
192278
202278
212278
222080
232080
242080
251981
261981
271981
281882
291783
301783
311783

Chance of precipitation in October

Any precipitation

Letterkenny gets around 105 mm of rain over 17.1 wet days in October. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 55% and peaks near 61% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%151015202531
Rain chance (%)
152
252
352
453
552
652
752
852
951
1051
1151
1251
1352
1452
1552
1652
1753
1854
1954
2055
2156
2257
2358
2458
2559
2659
2760
2860
2960
3061
3161

Humidity in October

DryComfortableHumidMuggyOppressiveMiserable

Most of October feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, October lands in the dry band about 98% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
1937
2937
3946
4946
5955
6955
7964
8964
9973
10973
11982
12982
13982
14982
15991
16991
17991
18991
19991
20991
21991
22991
23991
24991
25991
26991
27991
28991
29991
30991
31991

Wind in October

Winds average 17 km/h in October.

Across October, daily wind ranges from about 17 km/h on the calmest days to 18 km/h at its breeziest. It stays fairly steady from day to day.

0510152025151015202531
Wind speed (km/h)Feels
117light breeze
217light breeze
317light breeze
417light breeze
517light breeze
617light breeze
717light breeze
817light breeze
917light breeze
1017light breeze
1117light breeze
1217light breeze
1317light breeze
1417light breeze
1517light breeze
1617light breeze
1717light breeze
1817light breeze
1917light breeze
2017light breeze
2117light breeze
2217light breeze
2318light breeze
2418light breeze
2518light breeze
2618light breeze
2718light breeze
2818light breeze
2918light breeze
3018light breeze
3118light breeze

Sunrise & sunset in October

DaylightNight

Daylight runs from about 11 h 18 min at the start of October to 9 h 06 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 132 minutes over October. Sunrise moves from 6:41 AM to 7:42 AM, and sunset from 5:59 PM to 4:47 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
111.36:415:59
211.26:435:56
311.16:455:53
411.16:475:51
511.06:495:48
610.96:515:46
710.86:535:43
810.86:555:41
910.76:575:38
1010.66:595:36
1110.57:015:33
1210.57:035:31
1310.47:055:28
1410.37:075:26
1510.27:095:23
1610.27:115:21
1710.17:135:18
1810.07:155:16
199.97:175:14
209.97:195:11
219.87:215:09
229.77:235:07
239.67:265:04
249.67:285:02
259.57:305:00
269.47:324:58
279.47:344:55
289.37:364:53
299.27:384:51
309.17:404:49
319.17:424:47

Solar energy in October

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in October, about 1.46 kWh/m².

For context, solar energy here swings from a low near 0.42 kWh/m² to a high of 4.85 kWh/m² in May across the year — October's 1.46 kWh/m² falls in the middle.

00.511.522.5151015202531
Solar energy (kWh/m²)Level
11.9Dim
21.9Dim
31.9Dim
41.8Dim
51.8Dim
61.8Dim
71.7Dim
81.7Dim
91.7Dim
101.6Dim
111.6Dim
121.6Dim
131.6Dim
141.5Dim
151.5Dim
161.5Dim
171.4Dim
181.4Dim
191.4Dim
201.4Dim
211.3Dim
221.3Dim
231.3Dim
241.2Dim
251.2Dim
261.2Dim
271.1Dim
281.1Dim
291.1Dim
301.1Dim
311.0Dim
Planning a trip in October

Is October a good time to visit Letterkenny?

Our two travel scores rate October for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

2.8
Sightseeing
6th-best month of the year
Beach & pool
never really warm enough

October is a weaker month for outdoor sightseeing in Letterkenny.

What to pack for Letterkenny in October

From October's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In October, Letterkenny sees daytime highs around 13°C and nights near 8°C. Pack rain gear. Worth having: a warm layer. About 17 days see rain.

rain geara warm layer

Sea temperature near Letterkenny in October

The nearest coast averages about 13°C in October — 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.

10°15°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°C)Comfort
Jan9Bracing
Feb9Bracing
Mar9Bracing
Apr9Bracing
May11Bracing
Jun13Bracing
Jul15Bracing
Aug15Cool
Sep15Bracing
Oct13Bracing
Nov12Bracing
Dec10Bracing

UV index in Letterkenny in October

LowModerateHighVery highExtreme

Clear-sky midday UV in October peaks around 2. 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.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateLowMay 24UV 5Jan 1UV 0
UV index (midday)Level
Jan0Low
Feb1Low
Mar2Moderate
Apr3Moderate
May5High
Jun5High
Jul5High
Aug5Moderate
Sep3Moderate
Oct2Low
Nov1Low
Dec0Low
Location & terrain

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.

Londonderry County BoroughDerryOmaghColeraineSligoBallymenaAntrimPortadown

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.

3 km
199 m
16 km
452 m
80 km
706 m
treesgrasslandcroplandartificial surfaceswater
October weather nearby: Londonderry County Borough 28 km · Derry 28 km · Omagh 48 km · Coleraine 71 km · Sligo 89 km · Ballymena 94 km · Antrim 101 km · Portadown 101 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
Roman Catholic 69%none 15%Protestant 4%Orthodox 2%

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. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).