Translation:I love picnics during the summer when the weather is amazing.
"En skovtur" is usually a picnic. A walk in the forest would be "en (gå)tur i skoven"
I reported. Duo can't always cover all of the ways to say something, and I think this is just a case where this alternate expression wasn't considered yet. I put "in the summertime", and either one means "during the summer". (I think one could argue that one meaning of the Danish sentence would not translate to these alternatives, but it is a silly meaning to assume where you're identifying the one summer that had great weather. But that still would not invalidate the alternate translations without giving us such a context to assume that meaning.)