Do Pokemon have specific spawning areas and times?

What you found are called Nest (https://pokemongohub.net/post/wiki/nests/) They are a specific places on the map where certain pokemon will spawn more frequently. The pokemon change every 2 weeks.

As for the night part, Growlithe is only a fire pokemon so it is not affected by the greater spawn rate of ghost/dark pokemon at night. (https://pokemongohub.net/generation-2/researching-nocturnal-specie-pokemon-go-generation-1-2/)

Water pokemon are known to spawn more next to water. (https://rankedboost.com/pokemon-go/catching-locations/#water)

To know which pokemon are in which next you can go here : https://thesilphroad.com/atlas

Growlithe may also spawn more often in areas where they would usually be a rare spawn (such as certain parks), during Sunny/Clear weather.

It doesn't necessarily mean it is a nest; nests you should see frequent spawns of a specific pokemon that may not normally appear at that location, and regardless of weather (though even more frequent if weather boosted).