How do winter and summer affect the length of days at the equator?

The axis of rotation of the earth is not perpendicular to its orbital plane. The North Pole is tilted towards the sun for half the year and the South Pole is tilted towards the sun during the other half. As a result of this, the length of days during summer and winter change as we move towards the poles from the equator. At the equator, the length of days remains approximately the same during summer as well as winter and the time difference between sunrise and sunset is 12 hours throughout the year. As the earth moves around the sun its orbital distance from the sun is not the same as the orbit is not a circle. At the peak of summer at the equator, the earth is closest to the sun, and when the earth is farthest from the sun it is winter at the equator.