This is the first day of spring in India (Northern Hemisphere). On
the fifth day of the waxing moon one should celebrate the coming of
spring to Vrndavana by offering Krishna many types of leaves and
flowers, and fresh shoots of sprouting grasses. Things that
symbolise life and new growth.
Following in the footsteps of the Vraja-basis of Vrindavana, one
should paint designs on His (Krishna's) body and perform a special
aratrika for Him. It is appropriate to offer yellow flowers
too.
The vasanta raga should be played on this day. The Deities in the
temples, especially in Vrindavana wear yellow or yellow-green on
this day.
In places like Vrindavan, Mayapur, Jagannath Puri and Udupi many of
the women folk dress in yellow also. As it is the first day of
spring many fertility rites are performed at this time - for the
family, for the women folk, for the crops, for the cows, etc. It's
a very festive time.