Adriatic Sea and Weather

Adriatic Sea and Weather Sailing in Croatia - Useful Resources

The Adriatic Sea Facts

The Adriatic is the northernmost part of the Mediterranean Sea. It extends from the Strait of Otranto (where it connects to the Ionian Sea) to the northwest where it ends at the Veneto region in Italy. There are over 1,300 islands in the Adriatic and most of them are located along the Croatian coast.

Depth of the Adriatic Sea

The Adriatic is basically divided into three basins. The shallowest is located in Istria, where the depth does not exceed 50 metres. Moving south from Pula, the seabed mildly drops, making a long, narrow valley that extends from Žirje towards Italy. The biggest depth there is about 240 metres. From there, the bottom rises to Palagruža Reef, where the depth does not exceed 130 metres. Towards the south, the bottom drops steeply towards the South Adriatic basin, where the biggest measured depth is 1,233 metres.

Seabed of the Adriatic Sea

The appearance of the underwater relief is a result of tectonic movements, abrasion or erosion that happened several million years ago, in times when certain parts of the seabed were land or the coastal area. Uneven areas on the bottom are constantly reduced by sedimentation of detritus from the land. This process is rather slow but constant. The configuration of the seabed provides perfect conditions for the Adriatic’s rich and versatile flora and for you to explore.

Tides on the Adriatic Sea

The high and low tides have relatively small amplitudes in the Adriatic. In the southern part, the difference is rarely above some 40 centimetres, while in the northern part, it is somewhat bigger, so that it comes to 1 metre in Istria and the Gulf of Trieste. In some narrow channels and bays, the high tide can grow considerably during a strong sirocco. That phenomenon is characteristic of big and deep bays of the southern Adriatic. The tides are of a mixed type, which means that their rhythm is semidiurnal during the new and full moon and of a daily type during the first and the last quarter of the day. Their amplitudes are very irregular.

Sea Currents in the Adriatic Sea

Sea currents occur under the influence of winds, the difference in pressure, temperature, and the differences in salinity. With respect to the direction, they can be horizontal or vertical. There are also bottom currents, which appear as the consequence of the moving of water from warmer areas to colder ones, during which the surface layer gets cold and descends towards the seabed. Currents are weakly observable in the Adriatic. Their speed changes in particular areas, but it also depends on time periods. The prevailing currents in the Adriatic flow counterclockwise from the Strait of Otranto to the north, along the Croatian coast and back south along the Italian coast. The average speed of currents in the Adriatic is about 0.5 knots.

Salinity of the Adriatic Sea

The total quantity of salt dissolved in one kilogram of seawater is called salinity. It is usually expressed in per mileage. The salinity of the Adriatic Sea is 38.30 per mill average, i.e. there is 38.30 g of salt dissolved in 1 kg of water. In the northern part of the Adriatic, the salinity is somewhat lower than in the middle and southern parts because of the influence of the Po River. The salinity in the Adriatic is lower than in the Mediterranean as the Adriatic collects a third of the freshwater flowing into the Mediterranean.

Sea Temperature of Adriatic Sea

The annual changes in sea surface temperatures are quite significant in the Adriatic. The average annual temperature is 17.5°C. During the winter, the sea is the coldest and the average surface temperature drops to 11°C, but it can drop to about 7°C or lower in rare occasions. In the spring, the sea becomes warmer and the surface temperature rises to 18°C. In the summer the surface of the sea reaches a high average temperature of 22 to 25°C, and in the southern Adriatic and Istria up to 27°C.

Parts of the water column that have the same temperature, the thermoclines, are well distinguished in the Adriatic. These thermoclines are most evident in the summer months. We can notice the first thermocline at a depth of 3 to 5 metres, the next one is at about 12 metres and yet another one at 18 metres, while below 30 metres the temperature is mostly constant throughout the year. In the winter, the sea temperature tends to be the same throughout the water column.

Waves in the Adriatic Sea

Waves occur primarily as a result of wind. The bigger the reach, i.e. the surface across which the wind blows, the higher the waves will be. The Croatian coast with its numerous islands reduces the reach and that means that the waves stay relatively small and the sailing is safe and pleasant. Most often, the heights of waves in the Adriatic are between 0.5 and 1.5 metres, and they very rarely exceed 5 metres in the open sea during the winter.

Sharks in the Adriatic Sea

The Adriatic Sea is home to many shark species, including the Great White. However, shark attacks on humans are quite rare in Croatia when compared to. The last recorded shark attack in Croatia occurred in 2008, and the last recorded death caused by a shark was in 1974.

Climate and weather on the Adriatic Sea

The climate at the Adriatic is typically Mediterranean, with mild rainy winters, and hot and dry summers. The air temperature changes depending on the area. Thus, summer temperatures in July can rise up to 34°C in the northern part, while in the southern part they can rise even to 38°C. In the winter, the coldest temperatures are noticed in the northern Adriatic (even up to -16°C), while they will not have exceeded +6°C in the southern part.

Weather conditions in the Adriatic are affected by the general weather situation in the Mediterranean and local climate conditions. Generally speaking, light to moderate winds with few storms prevail until June. In July and August, a period of calm sets in and storms are more frequent. From September on winds are again stronger. 

Winds on the Adriatic Sea

The bura (bora) and the jugo (scirocco) are the main winds on the Adriatic. They prevail in the winter period from September to May. The prevailing wind in the summer is the maestral. Below you can check a short summary of winds on the Adriatic Sea, but we have also prepared an in-depth guide on Adriatic winds.

Bura

The bura is a cold and dry north-easterly wind. It blows from the continent, i.e. from the eastern side of the Adriatic towards the open sea and brings bright weather. It starts abruptly and blows in squalls toward the sea. It is strongest in the Velebit Channel and the Gulf of Trieste. The picture shows typical "bura" corridors: (1) Golf of Trieste, (2) Kvarner, (3) Velebit Channel, (4) Sibenik, (5) Split - Makarska, (6) Peljesac and (7) Dubrovnik. In the summer the bora blows as a local wind and lasts only a few days. In the winter it may continue for up to two weeks.

Jugo

The jugo is a warm, humid east-southeast wind. It is accompanied by heavy clouds and rain. It is not a sudden wind like the bora as it takes 36-38 hours to develop. It blows throughout the Adriatic. In the summer it may appear as a local wind and is more frequent in the southern part of the Adriatic. Between March and June it blows in the north Adriatic as well.

Maestral

The maestral is a local westerly wind which blows from the sea, mostly in the summer. It usually starts between 10 and 11 in the morning and reaches its greatest strength between 2 and 3 in the afternoon to die down at sunset. It brings good weather. It is usually accompanied by white clouds. While bura and jugo each in their own way offer sailors excitement and challenge, maestral guarantees pure pleasure during which you can give yourself to the sea without fear.

Other winds

The burin, a north-easterly, blows in the summer from the mainland, usually in the morning. The tramontana is a type of bora; it is a northerly. Another type of bora is the easterly Levante. Pulenat blows from the west and lebić from the south-west. The nevera, a violent westerly, comes as a storm or squall. In the summer months, storms in the Adriatic are sudden and violent and produce a short-lasting swell. The Adriatic storms have an advantage: they do not last long and some of them leave behind pleasantly cool air. During periods of high pressure, the Adriatic also has the classical rhythm of winds: winds from the land during the night and from the sea during the day.

Weather Reports

The coastal radio stations broadcast weather reports in Croatian and English several times a day. The reports include a general weather situation report, messages and the forecast for the following 24 hours. Weather reports are broadcasted at the following UTC times (UTC + 1 h = CET; CET + 1 h = CE summer time):

  • Rijeka Radio VHF Channel 24 – 05:35, 14:35, 19:35
  • Split Radio VHF Channels 21, 23, 07, 28 – 05:45, 12:45, 19:45
  • Dubrovnik Radio VHF Channels 04, 07 – 06:25, 13:20, 21:20

Sailing conditions on the Adriatic Sea per region

Sailing conditions in Istria

 

APR

MAY

JUN

JUL

AUG

SEP

OCT

WIND DIRECTION

S

S

SW

W

SW

NE

NE

WIND SPEED (KT)

10

10

10

10

10

10

10

AIR TEMP. (C)

13

17

21

24

24

21

16

Sailing conditions in Kvarner

 

APR

MAY

JUN

JUL

AUG

SEP

OCT

WIND DIRECTION

E

E

E

E

W

E

NNE

WIND SPEED (KT)

14

12

12

12

12

12

12

AIR TEMP. (C)

15

19

23

25

24

22

18

Sailing conditions in North Dalmatia

 

APR

MAY

JUN

JUL

AUG

SEP

OCT

WIND DIRECTION

WSW

SSW

WSW

WSW

WSW

NNE

NNE

WIND SPEED (KT)

16

16

14

16

14

16

16

AIR TEMP. (C)

14

18

22

25

25

21

16

Sailing conditions in Central Dalmatia

 

APR

MAY

JUN

JUL

AUG

SEP

OCT

WIND DIRECTION

ENE

SE

WSW

WSW

WSW

ENE

ENE

WIND SPEED (KT)

16

16

14

12

14

14

14

AIR TEMP. (C)

14

19

23

26

25

21

17

Sailing conditions in South Dalmatia

 

APR

MAY

JUN

JUL

AUG

SEP

OCT

WIND DIRECTION

SE

SE

SE

SW

SW

ENE

ENE

WIND SPEED (KT)

18

18

14

14

14

16

16

AIR TEMP. (C)

14

18

22

25

25

22

18

Why is Croatian water so clear?

Croatian water is known for its clarity due to several factors. Firstly, Croatia is located on the eastern coast of the Adriatic Sea, which has relatively low levels of pollution compared to other seas. The water is also clear because of the lack of major rivers flowing into the Adriatic near Croatia, which reduces sediment and pollutants in the coastal areas. Additionally, the Adriatic Sea has a high level of water circulation, which helps to maintain its cleanliness and clarity.

How was the Croatian coastline formed?

The Croatian coastline was formed through a combination of geological processes over millions of years. It is primarily a result of tectonic activity and the movement of the Earth's crust. The coastline is characterized by a mixture of limestone, dolomite, and other sedimentary rocks that have been shaped by erosion from the sea and other natural forces.

What is the sea by Croatia called?

The sea by Croatia is called the Adriatic Sea. It is a body of water separating the Italian Peninsula from the Balkan Peninsula, and it stretches from the Strait of Otranto in the south to the Gulf of Venice in the north.

Why is the Adriatic Sea so salty?

The Adriatic Sea is relatively salty due to its limited connection with other oceans. It is a semi-enclosed sea with only narrow straits connecting it to the Mediterranean Sea. As a result, the water in the Adriatic evaporates more quickly than it can be replenished by freshwater inflow, leading to higher salinity levels

Is the Adriatic Sea warm?

In general, the Adriatic Sea is warm during the summer months, with surface temperatures ranging from around 22 to 27 degrees Celsius (72 to 81 degrees Fahrenheit) in coastal areas. During winter, the sea cools down, with temperatures ranging from around 10 to 15 degrees Celsius (50 to 59 degrees Fahrenheit).

Where is the warmest sea in Croatia?

The warmest sea in Croatia is typically found along the southern part of the country's coastline, particularly in the regions of Dubrovnik and the Dalmatian Islands. These areas benefit from the Mediterranean climate and are known for their relatively warm sea temperatures during the summer months.

Which beach in Croatia has the clearest water?

Croatia is known for its many beautiful beaches with clear water. One of the beaches often mentioned for its crystal-clear water is Zlatni Rat (Golden Horn) beach, located on the island of Brač. However, it's important to note that the clarity of the water can vary depending on weather conditions, currents, and other factors.

Is the Adriatic Sea part of the Mediterranean

Yes, the Adriatic Sea is considered part of the Mediterranean Sea. The Mediterranean Sea is a larger body of water that encompasses several smaller seas, including the Adriatic, Ionian, Aegean, and Tyrrhenian seas.

What is the myth of the Adriatic Sea?

There are several myths and legends associated with the Adriatic Sea. One notable myth is the story of the nymph named Liburna, who was said to have fallen in love with the sea god, Neretva. Liburna's unrequited love caused her to cry so much that her tears formed the Adriatic Sea. This myth reflects the ancient connection between the people of the region and their dependence on the sea for their livelihoods.

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