This is the 1473rd most frequent Russian word.
месяцы
"Months."
Here, 'месяцы' (months) is used as the plural subject of the sentence, denoting units of time within a year.
В году двенадцать месяцев.
There are twelve months in a year.
In this context, 'месяцы' refers to the collective periods of time characteristic of the fall season.
Осенью месяцы становятся прохладными.
In the fall, the months become cooler.
Here, 'месяцы' references specific months that seem to subjectively pass by at a different perceived pace.