This falls once in a month, i.e. mostly on the last Tithi of every Shukla Paksha. Lord Krishna in Srimad Bhagwat Gita has said that he is the light in the moon, (Chapter 7 Stanza 8) and of all the planets he is the moon (Chapter 10-Stanza 21). Moreover in Chapter 15 Stanza 12 and 13 Lord Krishna says “You should know the brilliance of the moon which enlightens the entire world is actually mine. It is he who permute the earth and supports all beings with his energy, he becomes the moon and provide succor and nourishment to all vegetation”. God is in full form on Poonam and hence the devotees throng in huge numbers at Shrinathji for Darshan. It is on this day one feels extra presence because the Divine Grace is fully showered.
Therefore one will notice that people come from various places to receive the blessings of Shrinathji.