Lol, I don't like Cuomo but it's an objectively pretty good approval rating. Even in blood red or ocean blue states, many disapprove of the executive from the same party. Gubernatorial politics aren't nearly as polarized as Presidential ones in that regard. Just take a look at this:
https://ballotpedia.org/Gubernatorial_approval_ratings
Cuomo is more popular than Tom Wolf and Jerry Brown.
It's really not a great number. The context of the Buffalo Billion scandal, the COR and Kaloyeros convictions, and internal Democratic wrangling over the State Senate, among other things, is important here.
It
is a decent approval rating compared to Paterson, Spitzer, or third-term Pataki, but those are not helpful comparisons. And Pennsylvania and California are states with different political cultures, although I'd also take issue with describing Jerry Brown as popular - my impression was that he'd spent much of his final year in office pissing various groups off and taking flak for California's housing crisis.
e: See
here for Quinnipiac's trends. 43% is as high as his disapproval rating from this firm has ever been, and 49% is only slightly higher than his lowest ever approval. His favorability numbers are much worse than they were throughout his first term. Siena's numbers, to the extent that they aren't total garbage, tend to be consistent with this. These are much worse than his numbers were during his first re-election contest in 2014.