Being outdoors and farming or gathering plants, you would notice having more or fewer hours of sunlight. You might be pretty sure the longer sun hours would come back, but you'd like to know for sure. And once you start measuring shadows, you're going to get it close enough, even without a henge.

Tirns out ancient people had less bullshit to deal with and the weord crap they got obsessive about was, like, the sky and shit.

And maybe they were also better at math than us, but you cant prove that.

And if you can; fight me.

People in the past had ridiculous amounts of free time. We take it for granted that we’re so busy working all the time to survive but life wasn’t always this busy. Hunter-gatherers had way less to do than we do. They didn’t need to spend all their time trying to pay rent or put food on the table. They also didn’t have the huge amount of media we have to consume.

So what did they do with their free time? They spent it observing nature around them. They watched the sun, the moon, and the stars very carefully. They gave names to the constellations and told stories about them. They learned the cycles of nature just as we learn the work and entertainment schedules that dominate our lives.

Yeah, sitting outside a lot chatting it would drive me nuts that the sun set slightly off each day and I would pester everyone who would listen to me about it until satisfactory answers were found. I’d be like “and then it just stops and goes back the other way! I am going to roll this rock out into a field and this other rock to sit on and put smaller rocks to mark the horizon until next spring!” And people would call me crazy and ask me why I care about such stupid things when I should be a good little villager having babies and skinning animals like a normal person.

In the beginning, there was just one TV channel with four seasons of a single show, and they'd just keep playing it every year. Everyone on earth had nothing else to watch. Very slow burn, the plot was Light.

People that wouldn't notice that always existed, as do now.
Same goes for people that do notice.

And them people advance science, so others can read about it on their phones.

When your food supply depends on the sun, you tend to pay attention to these kinds of things.

I think people here might be overthinking it. It's just counting daylight hours, the solstices are the longest/shortest days. The further from the equator you are the more obvious it is. There's around 10 hours more daylight in summer where I am so you can make a reasonable estimate of the solstices without using any timing devices, most people would notice that.

Because autistic people have always been here, and that one kid was obsessed with tracking a slight change in the sun every day for 6 years.

Math.

Because at that time people didn't have magic black squares to bury their heads on so they couldn't pay attention to nature.

There was a lot of boredom. Also curiosity stemming from "days seem short when it's cold and long when it's hot"

That bokeh effect in the background is so pretty.

Sky magic? How can anyone NOT pay attention?

Might have. There wasn't as much going on.