The Earth is closest to the Sun in January, in the depths of the northern winter.
The question
In January, the Earth is closer to the Sun: so why is it winter in the northern hemisphere?
What you do Run through the year: the Earth goes round the Sun, its axis always tilted the same way. Change the latitude or the tilt, and watch the height of the Sun, the length of the day and the energy received.
Without JavaScript, here are the animation’s data.
| Fact | Value | Source |
|---|---|---|
| Tilt of the Earth’s axis of rotation | about 23.4° | 1 |
| Solar energy received in January compared with July (effect of distance) | about 7% more | 2 |
| Date | Height of the Sun at noon | Length of day | Energy received over the day (equinox = 100) |
|---|---|---|---|
| June solstice | 68.4° | 15 h 25 min | 163 |
| March and September equinoxes | 45° | 12 h | 100 |
| December solstice | 21.6° | 8 h 35 min | 38 |
The values in the second table, and in the animation, are calculated: spherical geometry, an orbit assumed to be circular, with no atmosphere or refraction. The effect of distance is added separately, from the article’s figure (7%).
The takeaway The distance to the Sun changes the energy received by only about 7%. The tilt changes it far more: without it, no seasons.
Photo credits 4
- The Sun in visible light, photographed by NASA’s SDO satellite on 10 August 2024. NASA/SDO, AIA, EVE and HMI science teams, Public domain, source
- The Earth photographed on 7 December 1972 by the Apollo 17 crew on their way to the Moon: Africa, Antarctica and the Arabian Peninsula are visible. NASA, Apollo 17 crew, Public domain, source
- The Earth seen by the Meteosat satellite on 21 December 2010, 20 March, 21 June and 20 September 2011 (NASA). NASA (Meteosat images), Public domain, source
- Blue Marble: Next Generation, with land topography and sea-floor bathymetry, in equirectangular projection: map produced by Reto Stöckli, NASA Earth Observatory (NASA Goddard Space Flight Center). Reto Stöckli, NASA Earth Observatory, modified by NordNordWest, Public domain, source
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Sources 2
Williams, David R., “Planetary Fact Sheet – Metric”, NASA Goddard Space Flight Center (NSSDCA), updated 18 March 2025, row “Obliquity to Orbit (degrees)”, column Earth (third value; the columns run from Mercury to Pluto, with Moon after Earth).
Obliquity to Orbit (degrees) 0.034 177.4 23.4 6.7 25.2 3.1 26.7 97.8 28.3 119.5
Open access open the source · checked on 28 October 2026
StarChild Team, NASA Goddard Space Flight Center (HEASARC), “When is Earth closest to the Sun?”, StarChild, answer to the question of the month (January 2003).
Relatively speaking, Earth's distance from the Sun doesn't change all that much throughout the year, nevertheless there are measurable differences in solar heating that result from our planet's slightly elliptical orbit. Averaged over the globe, sunlight falling on Earth in January is about 7% more intense than it is in July.
Open access open the source · checked on 9 September 2026