Answer:
The time of year Proserpina is with her mother
Step-by-step explanation:
In the beginning Proserpina is a young girl who loves to collect flowers and loves everything around. She is innocent and joyful.
Later in the myth she is taken to Hades and when she is finally rescued it is revealed she ate a single pomegranate seed and must stay in underworld for 6 months each year this time is represented as winter and fall when Ceres (her mother) is sad because she does not have her daughter at her side therefore is cold and harsh during this time of year but during summer and spring when Proserpina is at her mother's side Ceres is full of joy and the world is beautiful and flowers grow.
Spring is symbolized the time of year Proserpina spend those 6 months with her mother and the world thrives.
Hope this helps and good luck!