North Sea warming accelerates, bringing heavier autumn rains to Dutch coast

The North Sea has warmed by 1.7 degrees over 40 years, with coastal areas heating faster. This change leads to milder winters and heavier autumn rainfall, directly impacting weather patterns and daily life in the Netherlands.

Key Data Point	Value
Average North Sea temperature	~10°C (1982-2024)
Warming trend (Dutch coast)	+0.4°C per decade
Warming trend (North Scotland)	<0.2°C per decade
Total warming (past 40 years)	~1.7°C
Seasonal warming (spring)	0.5°C per decade (strongest)
Seasonal warming (autumn)	0.3°C per decade (weakest)
Depth (southern North Sea)	20-50 meters
Depth (northern North Sea)	200-300 meters
Coastal temp range	<2°C (Feb) to >20°C (Aug)
North Scotland temp range	7-14°C

The Royal Netherlands Meteorological Institute (KNMI) monitors climate trends, including sea temperatures, to inform government policies on climate adaptation and public safety. Their data helps predict weather extremes and long-term environmental changes affecting the Netherlands.

The summary and analysis above were generated by European AI

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Read the full translated article below

The North Sea is warming up, but not everywhere or at the same rate in every season

March 2, 2026

Around this time of year, the North Sea is typically at its coldest. However, the seawater is now cooling less severely than it used to. Over the past 40 years, the North Sea has warmed by approximately 1.7 degrees. This warming varies by season and region. A warmer North Sea also leads to increased precipitation, particularly in coastal areas during autumn when winds blow from the sea.

North Sea warming up

Thanks to satellites, we have precise data on the surface temperature of the North Sea and how it has changed. Between 1982 and 2024, the average temperature was around 10 degrees (Image 1, left). The water is slightly warmer along the Dutch coast and cooler toward the Atlantic Ocean, beyond Scotland.

The warming trend differs by region (Image 1, right). Near the coast, temperatures have risen the most, while the increase is smaller toward the Atlantic Ocean. Along the Dutch coast, the temperature has risen by about 0.4 degrees per decade. North of Scotland, the increase is less than 0.2 degrees per decade. As a result, temperature differences within the North Sea have grown larger.

Temperature changes significantly throughout the year

The North Sea is not very deep. In the south, it is 20 to 50 meters deep, while toward Norway, it deepens to 200 to 300 meters. In spring and summer, the top 20 to 30 meters warm up significantly due to sunlight. In autumn and winter, this water cools again (see animation in Image 2).

Along the coast, seasonal temperature differences are the greatest: from less than 2 degrees in February to over 20 degrees in August—a difference of about 18 degrees. North of Scotland, where the sea is much deeper, temperatures fluctuate far less, ranging between roughly 7 and 14 degrees.

Another notable difference is between winter and summer. In winter, the sea becomes warmer as you move away from the cold coast. In summer, the opposite is true: the water near the coast is warmer than further out at sea.

Warming stronger in summer than in winter

The extent and pattern of warming vary across seasons (Image 3). The strongest warming occurs in spring (0.5 degrees per decade along the coast in the square shown in Image 3), while the least warming is observed in autumn (0.3 degrees per decade in the same area). In summer, warming is most pronounced in the middle of the North Sea, whereas in other seasons, it is strongest near the coast.

Warming over land stronger than over sea

The average annual temperature of the North Sea along the Dutch coast is 1.2 degrees higher than in De Bilt (Image 4). Year-to-year variations are nearly identical, as is the average warming over the entire period (+1.7 degrees). Further from the coast, the warming trend is slower. The main reason is that evaporation over the sea increases more with warming than over land, and evaporation has a cooling effect.

Why is the sea warmer than the land?

It takes more energy to heat the sea than the land, which is why the sea warms more slowly in spring and summer but also cools much more slowly in autumn and winter (Image 5). These mild winters contribute to the higher annual average temperature over the sea. In summer, temperatures over land and sea are nearly the same.

Why is the warming of the North Sea important?

The North Sea acts as a heat battery: the heat stored in summer is released again in winter, leading to milder winters in the Netherlands. In autumn, a warm North Sea, combined with westerly winds, fuels the development of showers that bring heavy rainfall, particularly along the coast. The warmer the North Sea, the more intense these showers become.

KNMI climate report by Frank Selten

The Jupyter notebook used to create the images is available on the KNMI GitLab.