Seasons in Finland

Last year, one of my daughters came home from school in early September talking about how autumn was here, autumn had begun, it was autumn now, etc. The weather was certainly crisp, and the leaves were starting to turn, but inside I was like, "autumn does NOT begin until September 21st, FINLAND."

But then my other daughter came home and started talking about autumn, too. So I asked my Finnish teacher about it and she said yeah, autumn in Finland starts around September 1st. Because that's when it starts to feel/act/look like autumn. Which, you have to admit, makes a lot more sense. I mean, does it make any sense that winter doesn't technically start until December 21st, even if in many cold places, the ground is already covered in snow by then? Or that spring starts when said snow is often still on the ground and even falling from the sky?

In the UAE, we joked that there were two season: summer, and really hot summer. We paid little attention to the official start dates of seasons because they were meaningless. We only paid attention to the "change in the weather" that came twice a year, accompanied by high humidity and heavy fog.

So when does a season really begin? When the calendar says it does, or when it starts acting like said season? In Finliand, it seems they adhere to the latter, based on my unscientific and highly anecdotal experience.