Go to Bovec in Slovenia
With mountains that linger in the blue sky, an emerald-green river Bovec offers picturesque scenes that are a must see for your bucket list.
Koper Weather in December
December in Koper typically sees daytime highs of 10°C (50°F) and nighttime lows of 4°C (39°F). Rainfall is also possible this month, so it's worth packing an umbrella. It falls within the winter season.
Rainfall in Koper in December
Rain is expected on roughly 12 days, totalling around 120 mm (4.7 in) for the month. Individual showers can be quite heavy this month. A proper umbrella or rain jacket is worth having.
Temperature in Koper in December
Koper in December gets highs of 10°C (50°F) during the day and drops to 4°C (39°F) at night. The winter season takes place during December. Cold conditions persist throughout the day, so warm clothing is important from the moment you head outside. Nights fall to 4°C (39°F), which is cold enough to feel it indoors too. A good thick duvet makes all the difference for a comfortable night's sleep.
Sunshine in Koper in December
This month sees fewer sunny days, with about 95 hours of sunshine, perfect for those who enjoy cooler temperatures.December in Koper has its charm. However, if you're seeking pleasant, dry and sunny weather, our weather planner can help you explore other destinations in the world.
Koper Temperature in December
Min Temperature
4°C (39°F)
Max Temperature
10°C (50°F)
Chance of Rain
40%
Precipitation
120 mm (4.7 in)
Rainy days
12 days
Humidity
67% *
Sunshine
95 hours *
Percentage Sunshine
*
* Data from: Portorož, Slovenia (11 KM, 7 Miles).
Koper Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Koper - and find the best time to visit.
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Koper typically stay consistent throughout December, with daily highs averaging around 10°C (50°F). Nights are cold, with lows typically ranging from 1°C (34°F) to 4°C (39°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 Koper in December
Browse day-by-day weather records for Koper spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Koper historical weather extremes in December
Based on 49 years of weather observations (1976-2025), these are the most extreme conditions recorded in Koper.
- The hottest December day on record in Koper reached 20°C (68°F) (December 19, 1989).
- Koper experienced its chilliest December day on December 27, 1996, reaching only -3°C (27°F).
- The coldest night in December in Koper was on December 29, 1996, with a minimum of -10°C (14°F).
Best Places in Slovenia in December
Find out more about the weather in Slovenia and which places have the best travel conditions in this month. See all of Slovenia in December →
perfect weather
pleasant
tolerable
unpleasant
poor
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 Koper in December
Dress warmly and in layers for your trip to Koper in December. A good base layer system works wonders. Start with good thermal underwear, add something warm like a fleece sweater, then finish with a waterproof jacket on top. Expect heavy rainfall, so bring good rain protection and waterproof bags. With limited sunshine expected, sunglasses aren't a priority for packing.
What To Do in Koper 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
Koper 3-Day Forecast
More climate data for Koper
Temperature Rainfall Sunshine Humidity
See the full Koper climate overview or explore weather in Slovenia.
Popular in December
Where to go in December - average daytime high across popular destinations.
Piran
11°C (52°F) Portorož11°C (52°F) Ljubljana5°C (41°F) Bovec4°C (39°F) Maribor
5°C (41°F) Bohinj4°C (39°F) Bled3°C (37°F) Kranjska Gora2°C (36°F) Bucket list
Need travel inspiration? Check out our bucket list articles and be inspired.
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