The change in Earth’s distance from the sun is fairly minimal, however, and perihelion isn’t something you’d notice with the naked eye. At perihelion, Earth is about 91.4 million miles from the sun compared to roughly 94.5 million miles at aphelion in July.
“The Earth’s orbit is also constantly changing from interactions with the other planets in the solar system, especially the Moon and Jupiter, so the time of perihelion can shift by a few hours,” says Jason Steffen, assistant professor of physics at the University of Nevada, Las Vegas.
What perihelion does (and doesn’t) change
While Earth’s changing distance from the sun does affect our climate, perihelion does not have a drastic impact on our seasons.
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“Earth’s 23.5-degree axial tilt is the primary driver of our weather and temperature shifts,” says McGowan. As Earth orbits the sun, its tilted axis causes each hemisphere to alternately lean toward or away from the sun. When a hemisphere tilts toward the sun, days grow longer, and sunlight strikes the surface more directly. When it tilts away, days shorten, and sunlight arrives at a shallow angle. Together, these effects change the amount of solar energy reaching Earth’s surface by roughly 50 percent in the mid-latitudes, and by much more at high latitudes.