Final answer:
The tilt of the Earth's axis is the primary factor that controls the seasons. When the Northern Hemisphere is tilted towards the Sun, it receives more direct sunlight, resulting in warmer temperatures.
Step-by-step explanation:
The tilt of the Earth's axis is indeed the primary factor that controls the seasons. When the Earth's Northern Hemisphere is tilted towards the Sun during June, it receives more direct sunlight, leading to warmer temperatures. This is because the angle at which the sunlight hits the Northern Hemisphere is steeper, resulting in more concentrated and intense heat. In contrast, during December, when the Northern Hemisphere is tilted away from the Sun, the sunlight hits at a shallow angle, causing less concentrated heat and colder temperatures.