No, it isn't. The varying distance between the earth and sun has very little to do with the seasons, as illustrated by the fact that Summer in one hemisphere and Winter in the other hemisphere take place simultaneously. The main cause of the seasons on earth is the fact that the earth's rotation axis is not perpendicular to the plane of its orbit around the sun.
The Earth is tilted 23 degrees. As the Earth rotates around the sun the Hemisphere of the Earth that is closest to the sun is having summer. The hemisphere that is farther away is having winter. The Earths rotation every 24 hours has no effect on the seasons. It is the Earth's rotation around the sun that causes the seasons.