This is the 2842nd most frequent Russian word.
август
August (the eighth month of the year).
Here 'август' is used as an identifier for the month of the year, emphasizing its position in the season cycle.
Август — это последний месяц лета.
August is the last month of summer.
In this sentence, 'августе' is the locative form of 'август', used to specify the time period during which the activity is performed.
В августе я люблю ходить на пляж.
In August, I love going to the beach.
Here, 'август' is used nominally to represent the entity of the month as a subject being described.