eng gramma expert please come

Use of “that” to describe time

In time expressions, we omit “on” or “in” before these words: every, last, next, that, this, some.

The rule is applicable to “that”.

That March, that year…etc refer to a period of time in the past.
e.g. When I was five, I went to live on a farm. That year the weather was very hot and dry.

There is no need to say, “In that year the weather was very hot and dry.”