When I see pastel colors I think of youth, new beginnings, babies and innocence which are perfect descriptions for the Spring. Just like Nature where there are new shoots, flowers popping up, birds building nests and Nature in general getting those families started.
To me, some hues are more youthful such as Baby Blue, soft yellow, pink and light lavender much like the colors you see in a sunrise which are also new colors that start the day.
Eventually Baby Blue grows up to be Navy
Pink grows into a beautiful lady called Red
Lavender grows to be the strapping Purple
and yellow glows and glows and glows until she shines to her brightest!
Pretty cool isn't it?