いつの間にか

いつの間にか

"いつの間にか" means "before one knows it" or "unnoticedly."

The phrase "いつの間にか" is used to express something happening without one's awareness or notice.

昨日、いつの間にか時計が止まってしまった。

Yesterday, the clock somehow stopped without me noticing.

Here, "いつの間にか" conveys that the speaker was unaware of the gradual change in light.

気が付いたら、いつの間にか外は暗くなっていた。

I realized that it had somehow become dark outside.

In this sentence, "いつの間にか" denotes that the transition from spring to summer occurred unnoticed.

いつの間にか春が終わり、夏が始まっていた。

Spring ended and summer began before I knew it.