Pallavi, one question on your question.
Is your question more related to Tirupati "RATH" Yatra or is it Tirupati Darshan?
If it is rath yatra then I would suggest to go and check the calendar for the same. It is available online.
Or If, normal Tirupati darshan then for me the best time is mid Dec to Jan. This is the best time. Yes too crowded indeed but best weather to visit Tirupati and other temples nearby.