If you want your Froslass to have moves only Snorunt learns by level-up, then wait until Lv 37. Otherwise, you can do it as soon as you want to; the two share similar level-up movesets.
In respect to this, is Froslass or Glalie better?
For PvP, make sure to grab Froslass. If you want to maximize the number of points you can earn with a Pokémon, potentially using it more often in raid battles, Glalie is slightly better.
Additionally, does Snorunt have to be female to get Froslass? Thankfully, though, you can now get Froslass in Pokemon GO, as of early 2019. You will need a female Snorunt, 100 candies, and a Sinnoh Stone to do so.
Then, which evolution is best for Snorunt?
It is vulnerable to Fire, Fighting, Rock and Steel moves. Snorunt's strongest moveset is Powder Snow & Avalanche and it has a Max CP of 888. Snorunt evolves into Glalie, Froslass.
What level does Snorunt evolve at?
level 42
