Climate and monthly weather forecast
Koper, Slovenia

Weather in January

In January, the average sea temperature in Koper, Slovenia, is 10.3°C (50.5°F). Note: Swimming in 10.3°C (50.5°F) is considered life-threatening. Even a few minutes in 13°C (55.4°F) water is uncomfortable, and swimming below 10°C (50°F) may cause total loss of breathing control and cold shock, depending on a person's physique. Weather in January »

Weather in February

February is the month with the coldest seawater in Koper, Slovenia, with an average sea temperature of 9.3°C (48.7°F). Note: At temperatures below 10°C (50°F), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Weather in February »

Weather in March

In Koper, Slovenia, the average seawater temperature in March is 10.1°C (50.2°F). Note: Swimming in 10.1°C (50.2°F) is considered dangerous. Unprotected immersion in temperatures below 10°C (50°F) causes quickly maximum intensity cold shock with hyperventilation. Weather in March »

Weather in April

In April, the average sea temperature in Koper, Slovenia, is 13.1°C (55.6°F). Note: At temperatures below 10°C (50°F), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Weather in April »

Weather in May

In Koper, Slovenia, in May, the average water temperature is 18°C (64.4°F). Note: For swimming, a surface water temperature of 18°C (64.4°F) is not enjoyable for the majority. Weather in May »

Weather in June

In Koper, Slovenia, in June, the average water temperature is 22.8°C (73°F). Note: A person's cold intolerance, with sunshine, wind, and air temperature, are essential factors for enjoying swimming in 22.8°C (73°F) water. Weather in June »

Weather in July

July and August, with an average sea temperature of 24.8°C (76.6°F), are months with the warmest seawater in Koper, Slovenia. Note: A person's cold intolerance, with sunshine, wind, and air temperature, are essential factors for enjoying swimming in 24.8°C (76.6°F) water. Weather in July »

Weather in August

July and August, with an average sea temperature of 24.8°C (76.6°F), are months with the warmest seawater in Koper, Slovenia. Note: A person's cold intolerance, with sunshine, wind, and air temperature, are essential factors for enjoying swimming in 24.8°C (76.6°F) water. Weather in August »

Weather in September

In September, the average sea temperature in Koper, Slovenia, is 23.3°C (73.9°F). Note: A person's cold intolerance, with sunshine, wind, and air temperature, are essential factors for enjoying swimming in 23.3°C (73.9°F) water. Weather in September »

Weather in October

In October, the average sea temperature in Koper, Slovenia, is 19°C (66.2°F). Note: Swimming in 19°C (66.2°F) is not enjoyable for the majority. Controlling breathing becomes progressively more difficult as surface water temperature decreases below 21°C (69.8°F). Weather in October »

Weather in November

In November, the average sea temperature in Koper, Slovenia, is 16.1°C (61°F). Note: For most, swimming in 16.1°C (61°F) is not an enjoyable activity. Weather in November »

Weather in December

In December, the average sea temperature in Koper, Slovenia, is 13.2°C (55.8°F). Note: Swimming in 13.2°C (55.8°F) is considered dangerous. Unprotected immersion in temperatures below 10°C (50°F) causes quickly maximum intensity cold shock with hyperventilation. Weather in December »
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FAQ

When is the sea coldest in Koper?

February is the month with the coldest seawater in Koper, with an average sea temperature of 9.3°C (48.7°F).

When is Daylight Saving Time (DST) in Koper?

On Sunday, 27. March 2022, at 02:00, Daylight Saving Time starts in Koper, and the time zone changes from CET to CEST. Daylight Saving Time ends on Sunday, 30. October 2022, at 03:00, and the time zone reverts from CEST to CET.

When are the longest days in Koper?

June has the longest days of the year in Koper, with an average of 15h and 38min of daylight.

When is the sea warmest in Koper?

The months with the warmest seawater are July and August, with an average sea temperature of 24.8°C (76.6°F).

What is the month with the shortest days in Koper?

The month with the shortest days in Koper, Slovenia, is December, with an average of 8h and 46min of daylight.

Average sea temperature
Koper, Slovenia

Average sea temperature - Koper, Slovenia

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
Koper, Slovenia

Average daylight - Koper, Slovenia

The month with the longest days is June (Average daylight: 15h and 38min).
The month with the shortest days is December (Average daylight: 8h and 46min).

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