Average temperature in December is 8.6 °C
Average daytime temperature is 12.1 °C
Average night temperature is 5.4 °C
Absolute maximum temperature: 18.5 °C
Absolute minimum temperature: -0.6 °C
Number of sunny days: 11
Number of rainy days: 20
Number of snow days:
Precipitation sum: 107 mm
* Weather data for Koper Slovenia is based on climate observations for 2023 year
| December (°C) | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Maximum temperature | 18.5 | 17.1 | 7.1 | 8.3 | 10.2 | 10.8 | 11.5 | 10.7 | 10.3 | 10 | 13.8 | 12 | 12.3 | 12.5 | 12.7 | 10 | 10.9 | 11.3 | 12.6 | 12.2 | 11.5 | 12.9 | 15.2 | 15.4 | 13.3 | 11.6 | 11.7 | 11.6 | 12.3 | 11.6 | 12.6 |
| Apparent max temperature | 15.3 | 13.4 | 2 | 5.6 | 8.9 | 7.3 | 8.3 | 8.7 | 7.7 | 8.2 | 11.9 | 11.4 | 12.3 | 10.1 | 8.1 | 5.5 | 8.3 | 10.1 | 11.8 | 11.9 | 10 | 11.9 | 13.5 | 13.8 | 12.2 | 10.5 | 10.4 | 10.1 | 10.9 | 10.9 | 11 |
| Mean temperature | 14.2 | 12.3 | 4.7 | 4 | 7.3 | 7 | 6.1 | 7.3 | 7.2 | 7.3 | 9.7 | 9.8 | 11 | 9.1 | 8.6 | 7.2 | 7.2 | 7.9 | 8.2 | 7.4 | 7.4 | 8.7 | 9.9 | 10.6 | 9.9 | 9.1 | 8.8 | 8.8 | 9.7 | 9.7 | 10.8 |
| Apparent mean temperature | 8.3 | -1.2 | -5.2 | -5.7 | 1.9 | 0.7 | -1.1 | -0.5 | 1.8 | 1.8 | 2.5 | 4.8 | 8.6 | 3.8 | 1.6 | 1 | 1 | 2 | 0.8 | 0.4 | -0.2 | 3.2 | 2.7 | 4.1 | 5.2 | 4.5 | 2.8 | 3.4 | 5.8 | 6.6 | 5.9 |
| Minimum temperature | 9.1 | 5.5 | -0.2 | -0.6 | 5.2 | 3.6 | 2.8 | 3.9 | 5.1 | 4.1 | 5.3 | 6.4 | 9.8 | 6.3 | 5.9 | 5.6 | 5.1 | 4.5 | 4 | 3.4 | 3.8 | 6.3 | 6.9 | 6.5 | 7.3 | 6.9 | 5.2 | 6.1 | 7.9 | 7.8 | 7.4 |
| Apparent min temperature | 12 | 8.4 | -0.8 | 0.5 | 4.7 | 3 | 3.3 | 4.6 | 4.6 | 5.4 | 7.9 | 9.1 | 10.3 | 6.6 | 4.5 | 2.9 | 4.3 | 6.1 | 6.3 | 5 | 4.6 | 6.2 | 7.2 | 8.6 | 8.3 | 7.3 | 7.3 | 6.9 | 8.2 | 8.9 | 8.8 |
| December | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight duration (h) | 9 | 9 | 8.9 | 8.9 | 8.9 | 8.9 | 8.8 | 8.8 | 8.8 | 8.8 | 8.8 | 8.8 | 8.8 | 8.7 | 8.7 | 8.7 | 8.7 | 8.7 | 8.7 | 8.7 | 8.7 | 8.7 | 8.7 | 8.7 | 8.7 | 8.7 | 8.7 | 8.7 | 8.7 | 8.7 | 8.8 |
| Sunshine duration (h) | 1 | 4 | 7.8 | 4 | 0 | 7.7 | 7.7 | 5.2 | 7 | 6.8 | 3.8 | 0.4 | 0 | 7.6 | 7.5 | 7.5 | 7.5 | 7.5 | 7.5 | 1.7 | 5.7 | 7.5 | 7.5 | 6.7 | 7.5 | 4.3 | 1.2 | 2.9 | 3.6 | 4.1 | 0.5 |
| Precipitation (mm) | 17.3 | 27.6 | 1.5 | 0.9 | 12.3 | 0 | 0.8 | 2.5 | 2 | 9 | 1.3 | 1.5 | 22.2 | 0.4 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0.2 | 0.3 | 0.9 | 0.1 | 0.6 | 0.3 | 5 |
| Precipitation hours | 15 | 18 | 4 | 5 | 12 | 0 | 3 | 5 | 7 | 7 | 5 | 5 | 23 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 3 | 5 | 1 | 5 | 2 | 19 |
| Wind speed (m/s) | 31.2 | 36.3 | 29.4 | 14.4 | 20 | 20.8 | 11.7 | 12.4 | 11.3 | 8.9 | 16.4 | 6.9 | 10.1 | 15.5 | 25.8 | 20.9 | 19.5 | 5.7 | 7.1 | 16.9 | 15.9 | 16.4 | 17.2 | 14.2 | 12.3 | 10.3 | 8.7 | 13.7 | 10.6 | 7.2 | 27.5 |
In December 2023, the highest daytime temperature in Koper was 18.5°C.
While the minimum temperature at night dropped to -0.6°C.
The average nighttime and daytime temperatures during December in Koper are 5.4°C and 12.1°C respectively.
The precipitation sum in December is about 107 mm.