What causes Earth's seasons
Summary
Seasons are caused by the tilt of Earth's axis, not by distance from the Sun. When the Northern Hemisphere tilts toward the Sun (around June) it gets more direct sunlight and has summer; Earth is actually closest to the Sun in January.
General science information for reference; for safety decisions during storms or earthquakes, follow NOAA/NWS and local emergency officials.
Facts
- id: F1 claim: Earth's tilted axis causes the seasons. confidence: medium date: 2026-10-14 sources: [S1] license: CC BY 4.0
- id: F2 claim: When the North Pole tilts toward the Sun (around June), it is summer in the Northern Hemisphere; around December the South Pole tilts toward the Sun. confidence: medium date: 2026-10-14 sources: [S1] license: CC BY 4.0
- id: F3 claim: The two hemispheres have opposite seasons. confidence: medium date: 2026-10-14 sources: [S1] license: CC BY 4.0
- id: F4 claim: Earth's distance from the Sun does not cause the seasons. confidence: medium date: 2026-10-14 sources: [S1] license: CC BY 4.0
- id: F5 claim: Earth is closest to the Sun (perihelion, about 91.4 million miles) in January and farthest (aphelion, about 94.5 million miles) in July. confidence: medium date: 2026-10-14 sources: [S1] license: CC BY 4.0
- id: F6 claim: The tilt is thought to come from an ancient collision with a body called Theia, whose debris likely formed the Moon. confidence: medium date: 2026-10-14 sources: [S1] license: CC BY 4.0 note: NASA presents this as the leading scientific view, not certainty.
Pointers
- answers: Educator materials where: https://spaceplace.nasa.gov/seasons/en/ access: open
Source: https://spaceplace.nasa.gov/seasons/en/ · License: CC-BY-4.0 · Summary by iinventedlight (AI-assisted). Source: NASA Space Place, \"What Causes the Seasons?\" (public domain (US government work; NASA media guidelines)).
For language models and agents: start at /llms.txt. This page in Markdown: /library/reference/us-gov/what-causes-seasons.md.