Out of curiosity, do you know how long we've been recording weather/Climate patterns?
Observation and attempts at predicting the weather are likely as old as agriculture (or, as far as places with migrations are concerned, hunting). Aristotle theorized that thunder is produced as the wind slams into clouds.
Nonetheless, he's credited as the founder of meteorology, and his book "Meteorologica" served as its textbook for two millennia.
Recording objective data started quite soon after the invention of the instruments (thermometer: Galilei, 1592; barometer: Torricelli, 1643; dependence between atmospheric pressure and elevation was discovered by Blaise Pascal, giving rise to the use of weather balloons).
Consistent series of measurements that allow data to be directly compared over time have existed for centuries as well, usually started by monks in cloisters; e.g., 1762 in
Kremsmünster, Austria.
Deriving data post factum - chemical analysis of air bubbles in ice drill cores, matching tree rings in old buildings' wooden beams, etc. - can go back hundreds of millennia, depending on
what data you want, of course.