Do perihelion and aphelion effect seasons?

1 Answer
Jan 29, 2016

Perihelion and aphelion can have a small effect on seasons.


The main reason why we have seasons is due to the #23.5°# axial tilt.

The Earth is about #5,000,000km# closer to the Sun at perihelion than it is at aphelion. This means that there is more energy from the Sun arriving at the Earth at perihelion.

Currently perihelion occurs around 3 January and aphelion occurs around 3 July. Due to the fact that the southern hemisphere has a large area of ocean and the specific heat capacity of water is high, the southern hemisphere retains a lot of the heat during its Winter months. The Earth is actually a few degrees warmer on average in July than it is in January.

The date of perihelion is precessing at a rate of about a day every 70 years. In about 12,000 years perihelion will be in the northern hemisphere Summer. As the northern hemisphere has a lot of land area Summers will be warmer while perihelion is in the northern hemisphere Summer months.