Sumarliði is originally a byname meaning ‘summer-traveller’. Although it has also been suggested that it is a variation on Vetrliði ‘a bear in its second year’, the close association of the name with the Viking diaspora supports the ‘summer-traveller’ meaning.

These names likely arose in the Atlantic islands as there is one instance of Sumarliði from the early tenth century attributed to a man of Scottish birth, and several from the time of settlement in Iceland (c. 870-930). It does not appear until late in Norway, but there are several instances after c. 1320. The name is found in runic coin legends as the name of a moneyer operating in the Danish town of Lund between 1065 and 1075 – many of the moneyers in Lund actually came from England, where the name is relatively common. Sumarliði is also found in a place-name in Normandy.

Sumarliði is the first element in three instances of the place-name Somerby, and one of Somersby, Lincolnshire, and the name is also frequently reported independently as a personal name in Domesday Book for Lincolnshire.