Yes, that is right. The name Sommer is quite popular here in Germany. It can be found very often. It is said that it derives from jobs that were seasonally done in summer e.g. concerning the growing of summer grain. It could also be that our ancestors did some kind of trade selling articles which were only manufactured in summer or they sold their items only in summer. Other sources say that in the ninth century the name »Sumar«is mentioned. And so this name became the family name Sommer.