Best time to visit Letterkenny
Month-by-month weather averages for Letterkenny.
Letterkenny, Ulster, Ireland
°C
mm
- Average daily high and low
- Precipitation
- Good month
- Best month
- Made good or best by an event
| Month | Average daily high | Average daily low | Precipitation | Verdict |
|---|---|---|---|---|
| January | 7.3 °C / 45 °F | 3.4 °C / 38 °F | 106 mm / 4.2 in | neither best nor good |
| February | 7.9 °C / 46 °F | 3.4 °C / 38 °F | 94 mm / 3.7 in | neither best nor good |
| March | 9.2 °C / 49 °F | 3.8 °C / 39 °F | 87 mm / 3.4 in | neither best nor good |
| April | 11.7 °C / 53 °F | 5.3 °C / 42 °F | 73 mm / 2.9 in | neither best nor good |
| May | 14.2 °C / 58 °F | 7.7 °C / 46 °F | 89 mm / 3.5 in | neither best nor good |
| June | 16.2 °C / 61 °F | 10.3 °C / 51 °F | 90 mm / 3.5 in | good month |
| July | 17.3 °C / 63 °F | 11.9 °C / 53 °F | 109 mm / 4.3 in | good month |
| August | 16.9 °C / 62 °F | 11.9 °C / 53 °F | 118 mm / 4.6 in | good month |
| September | 15.6 °C / 60 °F | 10.4 °C / 51 °F | 92 mm / 3.6 in | good month |
| October | 12.9 °C / 55 °F | 8.3 °C / 47 °F | 112 mm / 4.4 in | neither best nor good |
| November | 9.6 °C / 49 °F | 5.6 °C / 42 °F | 111 mm / 4.4 in | neither best nor good |
| December | 7.9 °C / 46 °F | 3.9 °C / 39 °F | 115 mm / 4.5 in | neither best nor good |
Good and best months depend on more than temperature, rain and events. How they are chosen
Each activity on this page has its own good and best months, rated on twenty years of daily weather records. Which measures count, and how much, depends on the activity: humidity for exploring outdoors, wind for the beach, hiking and skiing, snow for skiing alone. Between them, the activities are rated on:
- Daytime highs
- Night-time lows
- How warm it feels
- Humidity
- How much of the day is sunny
- Hours of daylight
- Monthly rainfall
- How many days it rains
- Days of heavy rain
- Wind
- Snowfall and days with snow
- Major events, such as festivals
The chart shows the good and best months for exploring outdoors.
The event icon marks a month that an event lifts to good or best, such as a festival or a natural spectacle. Choose “Weather only” in the toolbar to rate the months on weather alone.
Best months by activity
Exploring outdoors
Mild days and nights, mostly dry and bright. The default for 'when should I go'.
- JJanuary: neither
- FFebruary: neither
- MMarch: neither
- AApril: neither
- MMay: neither
- JJune: good
- JJuly: good
- AAugust: good
- SSeptember: good
- OOctober: neither
- NNovember: neither
- DDecember: neither
- Good
- June–September
Why these months
June · good
In its favour: feels like (high) 14.6 °C / 58 °F, share of daylight that is sunny 61%, average daily high 16.2 °C / 61 °F, precipitation 90 mm / 3.5 in, days with heavy rain 2.1 days, average daily low 10.3 °C / 51 °F.
Against: wet days 15.8 days, relative humidity 81%.
July · good
In its favour: feels like (high) 16.2 °C / 61 °F, share of daylight that is sunny 58%, average daily high 17.3 °C / 63 °F, precipitation 109 mm / 4.3 in, days with heavy rain 3 days, average daily low 11.9 °C / 53 °F.
Against: wet days 18.4 days, relative humidity 83%.
August · good
In its favour: feels like (high) 15.4 °C / 60 °F, share of daylight that is sunny 60%, average daily high 16.9 °C / 62 °F, precipitation 118 mm / 4.6 in, days with heavy rain 3.2 days, average daily low 11.9 °C / 53 °F.
Against: wet days 20.1 days, relative humidity 85%.
September · good
In its favour: share of daylight that is sunny 57%, feels like (high) 13.5 °C / 56 °F, precipitation 92 mm / 3.6 in, average daily high 15.6 °C / 60 °F, days with heavy rain 2.2 days, average daily low 10.4 °C / 51 °F.
Against: wet days 16.2 days, relative humidity 85%.
An activity is listed only where it applies: skiing at ski destinations, beach and swimming at beach destinations. The nearest ski area is Glencoe Mountain Resort, 258 km away.
Weather averages
Monthly averages over twenty years, 2006–2025. Highs, lows and precipitation are in the chart at the top.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Feels like (high) | 3.3 °C | 3.7 °C | 5.2 °C | 8.3 °C | 11.6 °C | 14.6 °C | 16.2 °C | 15.4 °C | 13.5 °C | 10.1 °C | 6.3 °C | 4 °C |
| Days with heavy rain | 2.8 days | 2.3 days | 1.7 days | 1.5 days | 1.9 days | 2.1 days | 3 days | 3.2 days | 2.2 days | 3.1 days | 3.1 days | 2.9 days |
| Time rain usually falls | 2 am | 4 pm | 4 pm | 4 pm | 5 pm | 3 pm | 5 pm | 3 pm | 4 pm | 3 pm | 3 pm | 8 am |
| Sunshine per day | 3.7 h | 5.4 h | 7.1 h | 9.8 h | 10.7 h | 10.6 h | 9.6 h | 9 h | 7.2 h | 5.5 h | 4.2 h | 3.1 h |
| Relative humidity | 86% | 85% | 82% | 79% | 79% | 81% | 83% | 85% | 85% | 86% | 87% | 87% |
Air quality
Averaged over a shorter period (2022–2025) than the twenty-year averages above, and not counted towards good or best months.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Air pollution (PM2.5) 2022–2025 | 4.5 µg/m³ | 4.4 µg/m³ | 5.1 µg/m³ | 6.3 µg/m³ | 7.2 µg/m³ | 8 µg/m³ | 5.4 µg/m³ | 6 µg/m³ | 5.3 µg/m³ | 4.4 µg/m³ | 3.4 µg/m³ | 3.8 µg/m³ |
| Air pollution (PM2.5, daily peak) 2022–2025 | 7.2 µg/m³ | 7 µg/m³ | 8.5 µg/m³ | 10.3 µg/m³ | 11.9 µg/m³ | 12.6 µg/m³ | 8.7 µg/m³ | 9.4 µg/m³ | 8 µg/m³ | 7 µg/m³ | 5.9 µg/m³ | 6.5 µg/m³ |
- Good 15 µg/m³ or less
- Fair 15 to 25 µg/m³
- Moderate 25 to 37.5 µg/m³
- Poor 37.5 to 50 µg/m³
- Very poor 50 to 75 µg/m³
- Extremely poor over 75 µg/m³
Each figure is compared with the World Health Organization's guideline for a day's air, 15 µg/m³ or less, and with its interim targets above that. The words are ours: the WHO does not name its steps. The figures are modelled monthly averages, so single days can be well above them. The daily peak is the average of each day's highest hour, shaded on the same scale.