First, I appreciate that you put some real effort in the description. It meanders a bit here and there, but it does a pretty good job of explaining your thought process.
Second, here's my interpretation: the message of a farewell to winter is subtle, but it's there. some of the synths, specifically in the middle section to me sound very fluid and liquid smooth, if that makes sense.
Here's another example: in the beginning, before the rest of the instrumentation starts to kick in, there isn't a lot in the way of mids, which to me acknowledges winter. As you add instruments that contribute to mids and bass, the piece begins to feel warmer, like acknowledgement of Spring.
I'm not sure how many others will see it my way, so I'll give it the benefit of the doubt.
It's certainly peaceful to listen to.
More info about how I review music here: https://codefreq.newgrounds.com/news/post/1089806