September weather forecast
Koper, Slovenia

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Weather in September

Koper's weather in September heralds the arrival of autumn, with a slight diminution in sea temperature to 23.3°C (73.9°F). The receding heat signals the end of the hot summer days, adding a hint of freshness in the air. Yet, the lingering warmth and extended daylight hours make September an appealing month for late summer visitors. The city maintains its vibrant atmosphere, as the summer slowly gives way to the soft touch of autumn.

Sea temperature

In September, the average sea temperature in Koper, Slovenia, is 23.3°C (73.9°F).
Note: The cold tolerance of an individual, along with sunshine, wind, and the temperature of the environment, affects the enjoyment of swimming in 23.3°C (73.9°F) waters. (Olympic swimmers participate in waters ranging from 25°C (77°F) to 28°C (82.4°F).)

Daylight

In Koper, the average length of the day in September is 12h and 32min.
On the first day of the month, sunrise is at 06:27 and sunset at 19:42. On the last day of September, sunrise is at 07:02 and sunset at 18:47 CEST.
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Frequently asked questions

What is the water temperature in September in Koper?

In September, the average sea temperature in Koper is 23.3°C (73.9°F). For individuals prone to feeling cold, swimming in 23°C (73.4°F) is still regarded as intolerable. A wetsuit is not a necessity, but sunshine, wind, and air temperature are essential factors for relishing swimming at 23.3°C (73.9°F).

How many hours of daylight does Koper have in September?

In Koper, Slovenia, the average day length in September is 12h and 32min.

When are sunrise and sunset in September in Koper?

In September, on the first day of the month, sunrise is at 06:27 and sunset at 19:42. On the last day of the month, sunrise is at 07:02 and sunset at 18:47 CEST.

Average sea temperature in September
Koper, Slovenia

Average sea temperature in September - Koper, Slovenia
  • Average sea temperature in September: 23.3°C

The best months for swimming (with the highest average sea temperature) are July and August (24.8°C).
The coldest month (with the lowest average sea temperature) is February (9.3°C).

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Average daylight in September
Koper, Slovenia

Average daylight in September - Koper, Slovenia
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).

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Koper, Slovenia

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