The Earth's orbit around the sun is not a perfect circle. Around July 5, the Earth is at its farthest point to the sun -- about 5 million kilometers farther than when it's at its closest point around Jan. 4. But we're still warm here in Seattle, because the tilt of the Earth's axis is much more influential to our seasons than the slight change (astronomically speaking) in distance from the sun.
The Earth does get about 7% less sunlight in summer compared to winter, but there's more land mass in the Northern Hemisphere, which absorbs more sunlight.
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