ていく (auxiliary verb) - Clarification on nuance


I was revising the grammar for ていく and got this sentence from the Dictionary
of Basic Japanese Grammar.

> これからは寒くなっていく

The meaning the book gave was that "It will get colder (and continue to be
that way) from now on."

When it mentions "continue to be that way" does it mean it will:

1) get colder and remain at that level of coldness OR

2) continue to get colder and colder (increasing level of coldness) ~~until
the end of the process~~ (Edit: removed this extra text)

I am leaning towards option 2 because in that particular sentence, I read that
you can replace ていく with てくる to mean the exact same thing. And since てくる also
indicates the beginning of some process.

Hope someone can give an input to clarify if I am misunderstanding it. Thanks.




It's 2), "continue to get colder and colder over time". Unless I'm missing
something, `adjective + くなっていく` **always** refers to a gradual change.

By the way, to mean 1), you can say something like (急に)寒くなってその寒さがしばらく続く.

