Personally I believe that the ears are at least as influential on the brain as the nose it. I’m assuming that everyone has heard all the science behind the human nose and how it can trigger memories as the inner nose is the only area on the human body where a type of brain matter exists outside of the skull.
So, given the complexity and and proximity of the ears in relation to the brain you’ll soon notice that the ears are another type of sensory organ that is very closely (physically close) to the brain.
As far as your music choices, it could be the change in hormone levels in your system at spring time. It could be the smells that arrive with Spring, the sound of the returning birds. Any one of these, and there are many more triggers that I haven’t mentioned, triggers can cause your nervous system to inform your brain that it’s Springtime and that the body needs the hormones and chemicals that it will need during the spring season.
Finally, it’s also entirely possible that it’s not just one sense that is flicking the “Springtime” switch in your brain but rather a combination of all the things I mentioned in this post as well as bodily instincts that doctors are not even aware of yet.
Long post eh? Well, I hope it answers your question.