This is the first post I've ever replied to here in 15 years, and probably the last. But the comments in this thread triggered me pretty hard.
Our son's best friend at school is called Summer. Contrary to other replies, I've never once thought of it being a "childish" name, nor have any children in the school been bullied for having unique/rare names. My children have rare names, I've not seen any adverse impact as a result of this.
Objectively speaking, having a more unique name carries a considerable advantage for being remembered by others amongst the noise in our world. There's certainly a point to which a name may cause issues, due to other cognitive bias or personal preference etc, but Summer is certainly not one of them.
The naming of a child is a rare event, and having a story behind the name gives even deeper meaning.
Personally, I think Summer is a lovely name, and I can't see how that would affects a child's ability to be taken seriously as "a barrister or politician", as one of the other posters so crudely put it. If it was me, I would avoid "Summer-Rose" as a double-barrelled name, simply because the majority of people will default to using the first part of the name and ignoring everything after the dash. But I wouldn't see any issue with "Summer Rose ...", e.g. Rose as a middle name.
You might want to look at some of the subreddits on Reddit too, just try to avoid the echo chambers etc.
Hope this helps :)