〜てくる

About

The ～てくる structure is comprised of a て form verb + 来くる ("to come"). ～てくる describes something that moves physically or metaphorically toward a given current position in either time OR space.

E.g. 寒さむくなってきた。
"It has gotten cold."

Usually, when ～てくる describes something temporally, it describes a gradual change or an action that happens over an extended period of time.

E.g. 午後ごごから寒さむくなってくる。
"It'll get colder from the afternoon."

Summary

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  ～てくる describes something that moves physically/metaphorically toward a given current position in either time OR space

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  When used temporally, ～てくる tends to describe a gradual action