This is the 104th most frequent German word.
sogar
"Even."
The word 'sogar' emphasizes the exceptionality or unexpectedness of his action of going for a walk despite bad weather.
Er ist sogar bei schlechtem Wetter spazieren gegangen.
He even went for a walk in bad weather.
Here, 'sogar' is used to stress that children—an unexpected group in this context—possess the knowledge.
Sogar die Kinder wissen schon, wie man das macht.
Even the children already know how to do that.
The word 'sogar' highlights that the person succeeded in a surprising or notable challenge.