GRAMMAR DETAIL

てくる

have begun to; have come to

Follows a verb of change to show that a change that began in the past has progressed toward the present.

Examples

三月に入り朝の空気が暖かくなってきた。

Since the beginning of March, the morning air has been getting warmer.

歩いているうちに、空が暗くなってきた。

As I walked, the sky began to grow darker.

最近、日が長くなってきました。

Recently, the days have been getting longer.

Structure: A verb of change in the て form is followed by くる.
Basic usage: 最近、日が長くなってきました。 presents a recent change as having developed toward the present.

Developing change and emerging signs
- 暖かくなってきた can describe warming up to now, while 眠くなってきた can describe emerging sleepiness. Context determines when the change began and how far it has progressed.
Direction compared with ていく
- 増えてきた looks at growth leading up to a reference point; 増えていく looks at growth continuing beyond it. Distinguish the viewpoint on the change.