December weather forecastKoper, Slovenia
December
Weather in December
The weather in Koper during December fully embraces winter, marking a full circle in the annual weather cycle. The sea temperature sinks further to 13.2°C (55.8°F). The reduced daylight hours accompany the shortest day of the year towards the end of the month. These cold conditions bring out the festive spirit, adding charm to the cityscape with twinkling lights and heartening decorations. Despite the cold, Koper in December radiates warmth, welcoming the holiday season with open arms.Sea temperature
In Koper, in December, the average water temperature is 13.2°C (55.8°F).Note: While a brief time in 13.2°C (55.8°F) at 13°C (55.4°F) is already bracing, plunging below 10°C (50°F) can severely affect breathing and introduce a cold shock, relying on your physical state.
Daylight
With an average of 8h and 48min of daylight, December has the shortest days of the year.On the first day of December in Koper, Slovenia, sunrise is at 07:25 and sunset at 16:23. On the last day of the month, sunrise is at 07:45 and sunset at 16:31 CET.
Updated: Jan 24, 2024
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
In Koper, Slovenia, the average seawater temperature in December is 13.2°C (55.8°F). Swimming in 13.2°C (55.8°F) is considered dangerous. Unprotected immersion in temperatures below 10°C (50°F) causes quickly maximum intensity cold shock with hyperventilation.
With an average of 8h and 48min of daylight, December has the shortest days of the year in Koper, Slovenia.
The average day length in December is 8h and 46min.
In December, on the first day of the month, sunrise is at 07:25 and sunset at 16:23. On the last day of the month, in Koper, Slovenia, sunrise is at 07:45 and sunset at 16:31 CET.
Average sea temperature in December
Koper, Slovenia
- Average sea temperature in December: 13.2°C
The best months for swimming (with the highest average sea temperature) are July and August (24.8°C).
The coldest month (with the lowest average sea temperature) is February (9.3°C).
Average daylight in December
Koper, Slovenia
- Average daylight in December: 8h and 48min
The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).





