North Sea
Tidal range ( m ) ( from calendars ) Maximum tidal range ( m ) Tide-gauge Geographical and historical features
0.79-1.82 2.39 Lerwick Shetland Islands
2.01-3.76 4.69 Aberdeen Mouth of River Dee in Scotland
2.38-4.61 5.65 North Shields Mouth of Tyne estuary
2.31-6.04 8.20 Kingston upon Hull Northern side of Humber estuary
1.75-4.33 7.14 Grimsby Southern side of Humber estuary farther seaward
1.98-6.84 6.90 Skegness Lincolnshire coast north of the Wash
1.92-6.47 7.26 King 's Lynn Mouth of Great Ouse into the Wash
2.54-7.23 Hunstanton Eastern edge of the Wash
2.34-3.70 4.47 Harwich East Anglian coast north of Thames Estuary
4.05-6.62 7.99 London Bridge Inner end of Thames Estuary
2.38-6.85 6.92 Dunkerque Dune coast east of the Strait of Dover
2.02-5.53 5.59 Zeebrugge Dune coast west of Rhine-Meuse-Scheldt delta
3.24-4.96 6.09 Antwerp Inner end of the southernmost estuary of Rhine-Meuse-Scheldt delta
1.48-1.90 2.35 Rotterdam Borderline of estuary delta and sedimentation delta of the Rhine
1.10-2.03 2.52 Katwijk Mouth of the Uitwateringskanaal of the Oude Rijn into the sea
1.15-1.72 2.15 Den Helder Northeastern end of Holland dune coast west of IJsselmeer
1.67-2.20 2.65 Harlingen East of IJsselmeer , outlet of IJssel river , the eastern branch of the Rhine
1.80-2.69 3.54 Borkum Island in front of Ems river estuary
2.96-3.71 Emden East side of Ems river estuary
2.60-3.76 4.90 Wilhelmshaven Jade Bight
Geography -- Hydrology
Ocean currents mainly entering via the north entrance exiting along Norwegian coast • Localization of the tide-gauges listed• Tide times after Bergen ( negative = before ) • The three amphidromic centers• Coasts : marshes = green mudflats = greenish blue lagoons = bright blue dunes = yellow sea dikes= purple moraines near the coast= light brown rock-based coasts = grayish brown Temperature and salinity The average temperature in summer is 17 °C ( 63 °F ) and 6 °C ( 43 °F ) in the winter . [ 4 ] The average temperatures have been trending higher since 1988 , which has been attributed to climate change . [ 16 ] [ 17 ] Air temperatures in January range on average between 0 to 4 °C ( 32 to 39 °F ) and in July between 13 to 18 °C ( 55 to 64 °F ) . The winter months see frequent gales and storms . [ 1 ] The salinity averages between 34 and 35 grams per litre ( 129 and 132 g/US gal ) of water . [ 4 ] The salinity has the highest variability where there is fresh water inflow , such as at the Rhine and Elbe estuaries , the Baltic Sea exit and along the coast of Norway . [ 18 ] Water circulation and tides The main pattern to the flow of water in the North Sea is an anti-clockwise rotation along the edges . [ 19 ] The North Sea is an arm of the Atlantic Ocean receiving the majority of ocean current from the northwest opening , and a lesser portion of warm current from the smaller opening at the English Channel . These tidal currents leave along the Norwegian coast . [ 20 ] Surface and deep water currents may move in different directions . Low salinity surface coastal waters move offshore , and deeper , denser high salinity waters move inshore . [ 21 ] The Kelvin tide of the Atlantic Ocean is a semidiurnal wave that travels northward . Some of the energy from this wave travels through the English Channel into the North Sea . The wave continues to travel northward in the Atlantic Ocean , and once past the northern tip of Great Britain , the Kelvin wave turns east and south and once again enters the North Sea . [ 24 ]
The North Sea is a marginal sea of the Atlantic Ocean located between Great Britain (England and Scotland), Denmark, Norway, Germany, the Netherlands, Belgium and France. An epeiric (or shelf) sea on the European continental shelf, it connects to the ocean through the English Channel in the south and the Norwegian Sea in the north. It is more than 970 kilometres (600 mi) long and 580 kilometres (360 mi) wide, with an area of 570,000 square kilometres (220,000 sq mi). The North Sea has long been the site of important European shipping lanes as well as a major fishery. The coast is a popular destination for recreation and tourism in bordering countries, and more recently the sea has developed into a rich source of energy resources, including fossil fuels, wind, and early efforts in wave power. Historically, the North Sea has featured prominently in geopolitical and military affairs, particularly in Northern Europe. It was also important globally through the power northern Europeans projected worldwide during much of the Middle Ages and into the modern era. The North Sea was the centre of the Vikings' rise. Subsequently, the Hanseatic League, the Netherlands, and the British each sought to dominate the North Sea and thus access to the world's markets and resources. As Germany's only outlet to the ocean, the North Sea continued to be strategically important through both World Wars. The coast of the North Sea presents a diversity of geological and geographical features. In the north, deep fjords and sheer cliffs mark the Norwegian and Scottish coastlines, whereas in the south, the coast consists primarily of sandy beaches and wide mudflats.