"Summer is when the earthEarth is closest to the sun, and winter is when it's furthest away."
It's true that the earth'sEarth's orbit is slightly elliptical, but the effect of this, as far as seasons, is very small. For one thing, this wouldn't explain why the sun rises and sets at different times in different seasons, and if this were true, the whole planet would have summer at the same time.
The seasons are actually caused by the tilt of the Earth relative to its orbit around the Sun.