It’s all in the tilt. Our daylight hours change too, the closer you get to the poles. Right now, the northern hemisphere is tilted away from the sun, so we get less light hours and less direct light. The Southern Hemisphere is tilted towards the sun and experiences the opposite. There is a disparity, though, the Southern Hemisphere experiences it’s summer when we are closer to the sun. At 3 January we are approximately 91,500,000 miles away from the sun. At 3 July we are approximately 94,500,000 miles away. The variation in distance is only .33%, so that’s not really the issue. The issue is the tilt. If the orbit of the earth was more elliptical we wouldn’t be here. The orbit is more round than most solar systems in the Universe. .33% is really not that serious.