The earth is on an eccentric orbit. It's a small eccentricity (let's say e=0.01 https://www.wikiwand.com/en/Orbital_eccentricity) but it's there.
As it moves closer and farther from the sun the amount of energy being absorbed from the sun's light will change, and thus there will be a temperature shift dependant on earth's eccentricity (an "eccentric season")
The flux on earth and thus the rate it which it absorbs the sun's energy goes as r^-2, where r is the orbital radius. Thus the fractional change in flux is proportional to 4e. (taking into account the factor of 2 from the orbit ranging from a(1-e) to a(1+e) where a is the semi-major axis)
The effective temperature (assuming a blackbody) goes as (P)^0.25, where P is the incident power (= flux on earth * cross sectional area of earth).
Thus, for small e the fractional change in temperature should be ~ e.
For Earth, with a temperature of roughly 300 K, this gives a 3 degree temperature shift over an orbit.
I'm not sure I've ever heard anyone talk about this, and it doesn't seem negligible (especially given that there are parts of the world where seasonal temperature changes only by about 10 degrees http://ggweather.com/sf/narrative.html).
So my three questions are:
a) Is the above logic correct, are there (small) "eccentric seasons"
b) Where would they occur, specifically what latitude if any has a boosted seasonal change?
c) Is this something talked about that has just passed me by (wouldn't be the first time)?