Perihelion always occurs near January 4th, while aphelion lands near the 4th of July. The fact that the northern hemisphere of Earth has more land, while the southern hemisphere has more water, tends to moderate the impact of differences in sunlight between perihelion and aphelion. Sunlight raises the temperature of continents more than it does oceans. Aphelion sunlight is a little weaker than sunlight at other times of the year, but it nevertheless does a good job warming the continents. In fact, say climate scientists, northern summer in July when the Sun is more distant than usual is a bit warmer than its southern counterpart in January.
Most planets follow orbits that are more elliptical than Earth's.
Pluto's orbit, the most eccentric of all the planets, is so lopsided that Pluto is sometimes closer to the Sun than Neptune is. NASA scientists hope to send a probe to the retreating planet before Pluto's thin atmosphere freezes and falls to the ground. The solid lines indicate each planet's elliptical path around the Sun. The dotted lines show circular paths with the same mean separation from the center. Earth is almost exactly the same distance from the Sun at aphelion and perihelion, but the orbits of Mars and Mercury depart significantly from a circle.