Measurements:
°C
°F
CURRENT WEATHER
00:03
Koper
72°F
W 4 mph
Feels like: 72°F
Precip: 36%
World Resorts Slovenia Koper Weather

7 Day Weather Forecast

09.09
wed
DAY
76°F
W 4 mph
precip
70%
NIGHT
70°F
SE 9 mph
precip
87%
09.10
thu
DAY
80°F
SW 3 mph
precip
26%
NIGHT
70°F
S 3 mph
precip
39%
09.11
fri
DAY
78°F
S 2 mph
precip
18%
NIGHT
68°F
W 3 mph
precip
26%
09.12
sat
DAY
78°F
NW 1 mph
precip
17%
NIGHT
62°F
W 4 mph
precip
6%
09.13
sun
DAY
76°F
NW 5 mph
precip
1%
NIGHT
64°F
W 4 mph
precip
18%
09.14
mon
DAY
72°F
SW 4 mph
precip
13%
NIGHT
64°F
W 6 mph
precip
6%
09.15
tue
DAY
78°F
SW 6 mph
precip
1%
NIGHT
64°F
W 5 mph
precip
6%

Koper Sea Water Temperature in September, °F

Select Year: 2025 2024 2023

The average sea surface temperature in September 2025 for Koper was 24.0°F. The maximum and minimum values were 22.8°F and 25.3°F respectively.

Koper on the Weather Map

Best Time to Visit Koper
The most sunny months:
August 23 days
July 22 days
June 20 days
The most warm months:
August 89.2 °F
July 88.7 °F
June 83.7 °F
Warmest sea temperature:
August 81.7 °F
July 81.3 °F
September 76.5 °F
The most cold months:
January 45.0 °F
December 47.8 °F
February 48.1 °F
The most rainy months:
May 7 days
November 6 days
September 6 days
The most windy months:
March 6 mph
February 6 mph
November 6 mph
more details