Letterkenny Weather in December
December in Letterkenny sees daytime temperatures around 9°C (48°F) and lows of 4°C (39°F) at night. As the wettest month of the year, keep in mind that rainfall is at its highest.
Rainfall in Letterkenny in December
This month sees the most rain, so carrying an umbrella will ensure you stay dry. Looking at the last 30 years, the data shows about 24 days with rain, averaging 119 mm (4.7 in) for the month. Expect frequent rainfall this month, and not just light drizzle. When it rains, it tends to come down hard.
Temperature in Letterkenny in December
Letterkenny in December gets highs of 9°C (48°F) during the day and drops to 4°C (39°F) at night. The winter season takes place during December. Even at the warmest part of the day, temperatures stay low. Dressing warmly from the start is the sensible approach. At 4°C (39°F) overnight, it gets properly cold after dark. On the bright side, cold nights tend to make for excellent sleeping conditions.
Sunshine in Letterkenny in December
This month is characterized by fewer sunny days, with about 39 hours of sunshine. It's great for those who appreciate cooler, less sunny days.December in Letterkenny has its charm, but if you're looking for destinations with pleasant temperatures and sunny skies, our weather planner can help you explore other options in the world.
Letterkenny Temperature in December
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Letterkenny Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Letterkenny - and find the best time to visit.
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Letterkenny typically stay consistent throughout December, with daily highs averaging around 9°C (48°F). Nights are cold, with lows around 3°C (37°F).
Average temperatures in December
Daily Historical Precipitation
50-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in December
Historical weather records for Letterkenny in December
Browse day-by-day weather records for Letterkenny spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Letterkenny historical weather extremes in December
Based on 49 years of weather observations in Letterkenny between 1976 and 2025, these are the recorded extremes.
- Letterkenny recorded its highest December temperature of 16°C (61°F) on December 9, 2025.
- Letterkenny experienced its chilliest December day on December 22, 2010, reaching only -6°C (21°F).
- The lowest overnight temperature recorded in December was -14°C (7°F) (December 23, 2010).
Best Places in Ireland in December
Find out more about the weather in Ireland and which places have the best travel conditions in this month. See all of Ireland in December →
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).
What to Wear in Letterkenny in December
We recommend to layer up for chilly conditions in Letterkenny in December. You could start with thermal underwear or a good base layer to keep your core warm on the cooler days this month. Maybe also add a sweater or fleece, and top it off with a windproof jacket. High rain levels are expected, so pack waterproof gear and an umbrella or poncho. You can probably leave your sunglasses at home, because sunny days are pretty rare this month.
What To Do in Letterkenny in December
We rated the following activities from 1 (least suitable) to 10 (best) to do.
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Swimming4/10 -
Cycling4/10 -
Walking4/10 -
Camping3/10 -
Outdoor sports4/10
Letterkenny 3-Day Forecast
See the full Letterkenny climate overview or explore weather in Ireland.
Popular in December
Where to go in December - average daytime high across popular destinations.
Doolin
11°C (52°F) Cork11°C (52°F) Westport9°C (48°F) Kilkenny
9°C (48°F) Kenmare10°C (50°F) Killarney10°C (50°F) Galway10°C (50°F) Dublin10°C (50°F) 
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