Jet streams change position, location, and strength depending on the season. In the winter, areas in the Northern Hemisphere may get colder than in other periods as the jet stream dips "lower," bringing cold air in from the polar regions.
The jet stream shifts north and south seasonally; because there is less cold air, it retreats northward into Canada during the northern hemisphere's summer
The life of early hunter-gatherer societies was shaped by their physical environment. ... Early humans were hunters and gatherers whose survival depended on the availability of wild plants and animals.
