Everywhere that agriculture was invented modern humans developed accurate calendars to guide them regarding when to plant and harvest their crops.
Without clocks or modern tools, ancient Mexicans watched the sun to maintain a farming calendar that precisely tracked seasons and even adjusted for leap years.
From Science Daily citing:
Exequiel Ezcurra, Paula Ezcurra, Ben Meissner. "Ancient inhabitants of the Basin of Mexico kept an accurate agricultural calendar using sunrise observatories and mountain alignments." 119 (51) Proceedings of the National Academy of Sciences (2022) DOI: 10.1073/pnas.2215615119