The month August should be capitalised. The word august, meaning something impressive, does not need to be, unless it starts a sentence.
That sentence means that the speaker was born in the month of August.
Mr. Brown, a Leo, has an August birthday.
Simple Sentence
Lebron James' august performance all season gave him the MVP award
august 2 the end of darkest part of the year.
August means inspiring or admiring in this sentence.
August is the eighth month of twelve other months.
"She trembled with anticipation at the thought of being in the presence of such an august personage as the Queen of England".
Only the second sentence is correct: (John has been working here since August). Hope that helps. The first example could be correct if you susituted "is" for "was." Example: John was working here since August...although it would need to have something followed such as "John was working here since August, but he has since left the company.
Baby Serina Williams was inborn on August 19, 1996.
The opening of the store was tentatively scheduled for late August.