There are genres in which you may do the character naming early in your process, and there are other genres where the character naming should come after some substantial world building.
In contemporary fiction, you can generally look for appropriate names anytime. In fact, you may even start with a character name and “discover” the character’s story and plot afterwards.
If you are writing historical fiction about a place and time-period which you have studied, you may also name your characters early in the outlining process.
However, the more world building your novel will require is directly related to how much planning ought to go in before you name your characters.
Let’s take for example the werewolf namings I did a few weeks ago. As you may recall, I pointed out that if you werewolf was bitten s/he would have been named something unrelated to wolves or the moon or what-have-you; if your werewolf is instead a part of a werewolf society, with packs and power designations, then s/he may have been named something more obviously wolfy. I would challenge you to think that example even further, though, and to consider naming your society of werewolves with names related to their familial lines (e.g. the leader’s family would have more powerful and strong-sounding names, while the others may have more traditionally occupational names to signify their “worker” status). Or you could go with the cheesy/cutesy all the Alphas have Al- names (Alexei, Alejandro, Alegra), the Betas have B- names (Beth, Benji, Bartholomew), et cettera.
Fictional werewolves (usually) live in our contemporary world, so these characters could be named once their origin and familial structure is worked out, but before the entire plot is planned; however, characters in a future or alien setting would require more world building before naming.
Take for example this week’s King. The writer of this story ought to have worked out exactly what the society is like, what part technology plays (whether it is “nothing” as stated, or “steampunk” as also stated), and the power structure of the last 50-100 years that may affect the characters mores and what parents in that society would be naming their children. For example, when the King decided to have society revert to a Victorian-like society he could have insisted that everyone take on names from a Victorian Names Registry (like the registries that some countries use for baby naming). There would then be many Johns and Marys, and no Jaxons and Mackenzies, in this post-apocalyptic society.
Names are a reflection of society. In our modern society being unique and independent are important, so we give our children more unusual names. If your novel is set now or in the near future, you can easily assume the characters will have a selection of some of the currently popular names mixed with some strikingly-distinctive names. If, however, your novel society is not our own, then you need to discover what is important to the parents of that society, and how they would name their babies.