18.05
mon
mon
Day
66°F
E 5 mph
Precip.
80%
80%
Night
50°F
W 5 mph
Precip.
0%
0%
19.05
tue
tue
Day
66°F
E 4 mph
Precip.
100%
100%
Night
54°F
W 4 mph
Precip.
0%
0%
20.05
wed
wed
Day
75°F
SW 5 mph
Precip.
0%
0%
Night
55°F
W 5 mph
Precip.
0%
0%
21.05
thu
thu
Day
77°F
S 5 mph
Precip.
0%
0%
Night
57°F
W 5 mph
Precip.
0%
0%
22.05
fri
fri
Day
77°F
S 6 mph
Precip.
0%
0%
Night
61°F
W 6 mph
Precip.
0%
0%
23.05
sat
sat
Day
79°F
SW 6 mph
Precip.
0%
0%
Night
63°F
W 4 mph
Precip.
0%
0%
24.05
sun
sun
Day
79°F
SE 5 mph
Precip.
0%
0%
Night
63°F
W 4 mph
Precip.
100%
100%
Sea water temperature in May, °F
Show year:
2026
2025
2024
The average sea water temperature in May of 2026 was 62.0°F. The highest and lowest sea temperatures during the month were 65.3°F and 57.6°F.
Sea water temperature in June, °F
Show year:
2025
2024
2023
The average sea water temperature in June of 2025 was 75.4°F. The highest and lowest sea temperatures during the month were 81.1°F and 71.6°F.
Air temperature in Koper, °F
Precipitation total in Koper, in.
* Charts above show average data for the last 3 years.
Best time for vacation in Koper
Koper on a weather map
Places in Slovenia:
Name
°F
24 Hours Forecast
Koper
Local time: 02:40
May 18, monday
0300
46°F
W
5 mph
5 mph
0600
46°F
W
5 mph
5 mph
0900
61°F
NW
1 mph
1 mph
1200
66°F
E
5 mph
5 mph
1500
66°F
E
7 mph
7 mph
1800
64°F
NE
5 mph
5 mph
2100
52°F
W
3 mph
3 mph
May 19, tuesday
0000
50°F
W
5 mph
5 mph
