The highest day temperature in April 2025 was 70°F. The lowest night temperature was 37°F. The average values for day and night temperatures during April were 61.0°F и 53.8°F respectivly.

The average sea surface temperature in April 2025 for Koper was 56.8°F. The maximum and minimum values were 52.4°F and 63.2°F respectively.

Most of the days in April are sunny but you can also expect cloudy and gloomy days.

Precipitation total in April for Koper is 2.7 in. It makes april one of the least rainy months of the year.

The average wind speed in April is 6.2 mph. This value is relatively stable throughout the year.

We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for Koper in April is 8.5 hours.