COCA语料库有大量（2000多个）where引导定语从句修饰time的例句。以下仅举数例：

But why aren't we in a time where we've flipped the focus on business around to the front?

This is the time where the words of Albert Camus call for heavy consideration.

We live in the time where we have fictitious election results that elects a fictitious president.

There comes a time where a team has to just find a way to win a game. 

We're coming out of a period of time where everyone agreed about the right way to conduct research.

I can not remember of a single time where I would disagree with his analysis or recommendations. 

They knew there was going to be a time where the Earth had to go into almost total darkness. 

BNC语料库也有一些（30多个）类似例句。如：

You know there's a period of time where they, they sort of leave the grammar school and ...

And during the time where Attavan was getting a very bad press, I went back to the doctor and...

The opening of' The Age of Angkor' comes at a time where Australia is endeavouring to raise its profile among Asian countries. 

所以，可以认为在非正式语体（尤其是美国英语）中，where可以像when一样，引导定语从句。