Wave Height 

With multiple water bodies surrounding the country, Scotland experiences varied sea surface conditions around its coastline.   Patterns in wave height change through the seasons and between years, controlled by the multitude of factors affecting atmospheric and oceanic circulation (Hochet et al, 2021). The UK’s positioning near to the Polar Jet Stream – a high-altitude jet of fast flowing air – brings in frequent storms and high winds, contributing to wide annual variability in the country’s wave heights (NCAS, 2024). 

Fig. 1 displays the variability in significant wave height* around Scotland. The highest waves in the country are found off the Northwest Coast. This is due to the vast distance over which the wind can grow waves, flowing across the whole Atlantic Ocean (Marine Scotland Assessment, 2020). Off the East Coast in the North Sea the significant waves are slightly smaller, ranging between 2.72-3.00 and 1.51-1.80m within 100km of the East Grampian coastline (Scottish Government, 2014)
*the highest one third of waves

Marine Scotland Assessment (2020) examines seasonal differences in significant wave heights over 35 years around Scotland. They find winter significant wave heights to be an average of 5m in Western waters and 2-3m in Eastern waters, while summer significant wave heights are 2m in the West, and 1-1.5m in the East. This seasonal variation comes about due to the increase in extreme weather experienced during the winter. 

Looking to the future, how wave heights will change with the changing climate is still quite uncertain. It is believed that Scotland’s wave heights have increased in the last decade, with Castelle et al (2018) identifying an increase in winter average wave height in the Northeast Atlantic over the last 70 years.  In the coming decades however, Lobeto et al (2021) predict a decrease in annual North Atlantic significant wave height (fig. 1). This projected decrease in North Atlantic waters has been backed up by multiple studies (Lemos, 2021). Possible explanations for this decrease include a predicted shifting northwards of storm pathways, leaving the UK more sheltered, in addition to the topography of the Northern Atlantic Ocean restricting the northward flow of increasingly extreme waves from Southern waters (Lemos, 2021).