World Resorts Slovenia Koper Weather

Koper sea water temperature

Current sea water temperature:
+55.6°F
Minimum sea water temperature in December: 60.1°F
Maximum sea water temperature in December: 50.2°F
Average sea water temperature in December: 55.2°F

Sea water temperature for the last 10 days:

December 25 55.6°F December 20 54.7°F
December 24 55.0°F December 19 55.0°F
December 23 55.4°F December 18 55.2°F
December 22 56.1°F December 17 55.4°F
December 21 55.4°F December 16 55.4°F

When is the warmest sea in Koper?

Based on the data about daily sea water temperature for the last three years the warmest sea in Koper was noticed in August, July and September.

Monthly Sea Temperatures in Koper, °F

Sea water temperature in August, °F

Show year:
2025
2024
2023

The average sea water temperature in August of 2025 was 76.7°F. The highest and lowest sea temperatures during the month were 79.2°F and 74.1°F.

Sea water temperature in July, °F

Show year:
2025
2024
2023

The average sea water temperature in July of 2025 was 78.7°F. The highest and lowest sea temperatures during the month were 81.9°F and 76.5°F.

Sea water temperature in September, °F

Show year:
2025
2024
2023

The average sea water temperature in September of 2025 was 75.2°F. The highest and lowest sea temperatures during the month were 77.5°F and 73.0°F.

Best time for vacation in Koper

Sunniest months:
August 23 days
July 22 days
June 20 days
Warmest months:
August 85.0 °F
July 84.8 °F
June 80.2 °F
Warmest sea temp:
August 78.4 °F
July 78.1 °F
September 73.8 °F
Coldest months:
January 45.6 °F
December 47.8 °F
February 48.1 °F
Rainiest months:
May 7 days
November 6 days
September 6 days
Windiest months:
March 6.6 mph
February 6.5 mph
November 6.2 mph

Koper on a weather map

Koper
+34°F
W 11 mph
Feels like: +27°F
Precip.: 0%
Places in Slovenia:
Name
°F
+27°F
+34°F
+34°F
+27°F
+32°F
+28°F
+34°F
+34°F
+34°F
+34°F
+34°F
+32°F
24 Hours Forecast
Koper
Local time: 20:21
December 25, thursday
2100
34°F
W
11 mph
December 26, friday
0000
34°F
W
9 mph
0300
32°F
W
7 mph
0600
32°F
SW
8 mph
0900
32°F
W
7 mph
1200
45°F
SW
6 mph
1500
45°F
SW
4 mph
1800
39°F
W
5 mph
Units of measurement: °C / °F