Is 'at summer night' correct?

Question

At night in the summer it tends to get cold.

Is it possible to change into 'at summer night'?

Answer 1

In English, we use the phrase at night as an inseparable adverbial phrase. No other word can intervene between at and night in this usage.

The phrase is idiomatic. An exhaustive treatise on this and related idioms is available here at our sister site.

Answer 2

Yes, but it would not be idiomatic. It would be poetic. In everyday English we don't usually want to be poetic.

Both at night and in the summer are idiomatic expressions.

You certainly can put an adjective in between at and night, and people might even understand what you mean. But you would be departing from the norm.

For instance, it is pretty clear what at early night means, but we don't say this. We say at nightfall or some other expression. Instead of at late night we say late at night. So at night is a tough nut to crack. Having said that, if you write poetry and include at summer night, it could be appropriate and probably understood; poets often break the rules and use language in new ways.