So, the expressions such as "in winters", "in Aprils", "on weekends", "at weekends", "in mornings" are right or not?

Question

Cambridge Grammar

It says "I’ve got to go to London on Friday" (this Friday / next Friday -1 occasion)

but

"The office is closed on Fridays". (every Friday - repeated events)

It says "I often get tired in the afternoon." (seem like "every afternoon")

but it says nothing about "in afternoons"

It says "The garden is wonderful in the spring when all the flowers come out." (seem like "every Spring") but it says nothing about "in Springs"

It says "We usually go camping in July or August." (seem like "every July" ) but it says nothing about "in Julies"

It says "What do you usually do at the weekend (UK) / on the weekend (US)?" but it says nothing about "at weekends" or "on weekends".

But this site says we can say "at weekends" or "on weekends". Ex: I only see him at weekends.

So, the expressions such as "in winters", "in Aprils", "on weekends", "at weekends", "in mornings" are right or not?

Answer 1

Normally, when we use the temporal summers, winters, evenings, mornings, days, nights, etc, it is without the preposition in. The phrase "in the summer" can mean every summer, winter, etc.

Summers, we vacation at the beach.

Winters, we vacation in the mountains.

In the summer, we vacation at the beach.

In the winter, we vacation in the mountains.

In the summers, we ... ^{unidiomatic, when the meaning is every summer}

However, in the summers is idiomatic if the meaning is not "every summer" but a reference to multiple summers:

Scientists have pulled core samples from Antartica revealing information about the last five millenia there. In the summers where average temperatures were above 20C, there are large amounts of pollen.

[This may or may not be true. I just made the sentence up.]

We are likely to use those instead of the there, to reinforce the idea that we are pointing out a situation involving particular summers not every summer:

In those summers where average temperatures were above 20C...

Answer 2

I haven't come across any dialogue where I/someone else used 'in winters/Aprils' or 'at morning' (morning is a time of the day, idk how 'at' should even come across your mind)..

1) I love to play X-Box on weekends-- sounds correct to me.

similarly 'in mornings' seems fine as well.