Groundhogs
What I can interpret from this is that all of us human beings are groundhogs in a way; if we dwell more on our shadows, that is, our insecurities, worries and fears, winter, that is the rainy days in our life persist for longer... Vice versa, if we choose not to focus on the gloomier aspects of our life, spring, i.e better days arrive early because we are choosing to move past our trauma and our pain and are willing to embrace life and the changes it brings.
Another interpretation could be that ignorance is bliss. The more oblivious you are to a negative or toxic situation in your life (your shadow), the more happy-go-lucky you are and nothing bothers you so your better days (spring) are extended. So yeah. Here you go. My interpretation of your very interesting prompt :)