Earth's spin axis is tipped about 23.4°, and it keeps pointing the same way in space all year. For half the orbit the north end leans toward the Sun and for the other half it leans away. The leaning hemisphere gets steeper sunlight and longer days. That's summer. Distance from the Sun barely matters.
Watch the axis: it stays parallel to itself (pointing at the North Star) the whole way round. Drag Earth to move through the year, or drag anywhere else to turn the view. Sizes and distances aren't to scale.
Sunlight comes from the left. The gold ring is your latitude. The share of that ring in daylight is how long your day lasts.
Noon sunlight at your latitude. A low Sun spreads the same beam over more ground, so each square meter gets less energy.
At your latitude. The marker shows the selected date; hover or tap the chart to explore.
Earth's axis points toward Polaris all year. As Earth goes around the Sun, the same tilt leans the north end toward the Sun in June and away from it in December. Nothing wobbles from season to season. Earth just changes position.
When the Sun is high, a beam of sunlight lands on a small patch of ground. When it is low, the same beam is smeared across a larger patch and also passes through more air. Each square meter heats less.
The leaning hemisphere also spends more of each rotation in daylight. Stronger sunlight for more hours means much more total energy. Near the poles the summer Sun never sets, and in winter it never rises.
Earth is actually closest in early January, during northern winter, and farthest in early July. The orbit is nearly a circle: the distance varies by only about 3%, which changes sunlight by about 7%. If distance caused the seasons, both hemispheres would have summer at the same time. Instead they're always opposite.
Distance does have one subtle effect: Earth moves slowest when farthest away, so northern summer lasts 93.6 days and northern winter only 89.0.
Try setting the tilt to . Distance still changes over the year, but every latitude gets the same day length and Sun height every day. There are essentially no seasons.