The Earth is Hottest When It Is Furthest From the Sun On Its Orbit, Not When It Is Closest

Today I found out the Earth is hottest when it is furthest from the Sun on its orbit, not when it is closest.

During the period when the Earth is furthest from the sun (aphelion), the average temperature of the entire planet is about 4°F (2.3°C) higher than when it is closest to the sun (perihelion). On average, the intensity of sunlight falling on Earth during aphelion is about 7% less than during perihelion. Despite this, the Earth ends up being warmer during the period in which it is furthest away from the sun.

So what’s going on here? During the winter months, for the Northern Hemisphere, the overall temperature of the Southern Hemisphere, where it is summer, doesn’t change as much as the other way around. This is because a much larger portion of the Southern Hemisphere, compared to the Northern Hemisphere, is made up of water and water has a significantly greater heat capacity than land. On a similar vein then, during the summer for the Southern Hemisphere, the overall average temperature of the Southern Hemisphere doesn’t increase as much as the Northern Hemisphere does during its summer, for this same reason.

So the “tl;dr” version is: there is a lot more land in the Northern Hemisphere than the Southern Hemisphere; this land heats up much faster than water and water cools down much slower than land. So even though there is less intensity of sunlight during the summer in the Northern Hemisphere, the Earth’s average temperature is higher at this time when it’s furthest from the sun.

As you might have guessed then or already known, the seasons are not caused by the distance the Earth is from the sun, but rather are caused completely by the fact that the Earth is tilted on its axis 23.5°. This is why when it’s summer in the Northern Hemisphere, it’s winter in the Southern Hemisphere, and vice-verse. Without this tilt, there would be no seasons and the weather from day to day across the globe would be relatively uniform. In this case, there would only be a very slight variation in temperature as the Earth got closer or further away from the Sun, but for the most part, everything weather-wise would stay the same year round.

Bonus Facts:

  • The Earth orbits the sun at a speed of about 18.4 miles per second or about 66,600 mph.
  • The energy required to stop the Earth orbiting the sun then is about 2.6478 × 1033 joules or 7.3551 × 1029 watt hours or 6.3285*1017 megatons of TNT. For reference, the largest nuclear explosion ever detonated (the Tsar Bomba by the Soviet Union) “only” produced 50 megatons of TNT worth of energy. So it would take about 12,657,000,000,000,000 of those nuclear bombs detonated at the correct location to stop the Earth from orbiting the sun.
  • Along with orbiting around the sun at 66,600 mph, the Earth is also rotating at its axis at about 1,070 miles per hour. So you are simultaneously hurtling around the sun at 66,600 mph while sitting on a rock that is spinning at 1,070 mph. On top of that, our whole solar system is rocketing through space around the center of the Milky Way at around 559,234 mph. On top of that, our galaxy is hurtling through space at around 671,080 mph, with respect to our local group of galaxies. On top of that, for all we know, our entire Universe is hurtling through some unknown medium at some other ridiculous speed.
  • It takes approximately 225 million Earth years for our solar system to make one trip around the Milky Way.
  • The Earth is about 28,000 light years from the center of the Milky Way, on the outer rim. Most all the mass in the Milky Way is much closer in than we are; this is good because, if the density was the same out here as it is closer to the center, the increase in cosmic radiation would kill us all.
  • All planets in our solar system travel around the sun in elliptical orbits. The distance to the sun for the Earth varies by about 1.7%. We are closest to the sun in January (perihelion) at about 91.1 million miles (146.6 million km). We are furthest from the sun in July (aphelion) at around 94.8 million miles (152.6 million kilometers). The average distance from the sun to the Earth is known as 1 Astronomical Unit, (1 AU or about 93 million miles).
  • Summers in the Northern Hemisphere last 2 to 3 days longer than summers in the Southern Hemisphere. The reason why is that the Earth moves more slowly at aphelion than at perihelion.
  • The date of the period where the Earth is furthest away from the sun is called Summer Solstice. The date at which the Earth is closest to the sun, is called Winter Solstice. Summer Solstice happens on June 21/22. Winter Solstice happens on December 21/22.
  • In between these two points, there is a point in time where the Sun will appear to rise and set along the equator, so that the length of night and day is almost exactly equal everywhere on the planet. These two points are called the vernal equinox (March 20/21) and autumnal equinox (September 22/23).
  • The average temperature of the Earth year round is around 61°F (16.1°C). The average coldest temperature on the Earth, in Antarctica, is around -60°F or -51.1°C and the average of the hottest part of the Earth, in the Sahara Desert, is around 130°F (54.4°C).
  • The hottest temperature ever recorded on Earth was 136°F (57.77 °C) in El Azizia, Libya on the edge of the Sahara Desert. The second hottest, 134°F (56.6°C), was recorded in Death Valley, California in the Mojave Desert way back in 1913.
  • The coldest temperature on the Earth was recorded at Vostok, Antarctica on July 31, 1983 at -128.6°F (-89.22°C).
  • Unlike the Earth, which is only shifted about 23.5° on its axis, Uranus’ spins almost perpendicular to the sun. Interestingly, despite this fact, Uranus is hotter at its equator than at the poles. The reason why this is the case is not currently known.
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15 comments

  • I would like to say that this article about earth being warmer when farthest from the sun is completely misleading. A you need clarify, that earth’s core temperature may be warmer when farthest from the sun, not the atmospheric temperature. These are two distinct readings and the atmospheric temperature is most hottest when closest to the sun even though the earth’s core tempature may be cooler. there needs to be clarity between the readings you take the article’s you write.

  • The bonus fact beginning with “The date of the period where the Earth is furthest away from the sun” somewhat confuses solstice and perihelion/aphelion. I have long wondered how close perihelion was to northern winter solstice so a date range would have been more useful than “in January” in the bonus fact 2 bullet points above.

  • “the Earth ends up being warmer during the period in which it is furthest away from the sun.”

    http://www.quickanddirtytips.com/education/grammar/further-versus-farther?page=all

    Farthest, not furthest… (This is my biggest “pet peeve” – if it is distance you are talking about it is “far”)

  • Regarding the hottest temperature ever recorded, the Libya datum is no longer considered the hottest because of measurement errors. The hottest temp is now from Death Valley but it is not the 1913 datum but rather from some time in the 2000s.

  • My mom kept saying winter happened when its farther from the sun and summer happens when earth is closest to the sun. HA! I can prove her wrong now. Thanks!

  • simple. Farthest from the sun is warmer because it’s radiant energy.

  • The summer solstice is not when the earth is “farthest” away from the sun. The solstice is based on the 23.5 degree tilt. The summer solstice occurs when the axis/tilt is pointing directly at the sun. This is why the day is longest.

  • “Most all the mass in the Milky Way is much closer in than we are; this is good because, if the density was the same out here as it is closer to the center, the increase in cosmic radiation would kill us all.”
    Wouldn’t the radiation spread out to the point where it would be negligible by the time it got to our planet?

  • How can the Earth be a spherical object at all when the lines of latitude expand south of the equator?

    In 1773 Capt Cook sailed a total 69,000 miles at Antarctica, a distance nearly 3x the circumference at the equator.

  • Wayne A & Josette L Preisinger

    Once upon a time, there was nothing, nothing, but the endless boundaries of space. What could be in this space, to bring forth life? There was time, the six dimensions of space were there, up, down, right side, left side, and back-wards and forwards. The energy source of time could move in any direction, the dimensions of space could only move in their own direction. ( evolution begins with the energy sources ) When the energy source of time got all the energy sources of the dimensions of space together, the first physical unit came forth, an A T O M , ( at this time all the dimensions knew of all the other directions of space ) they did the same thing over, and over again making atoms with electrons, some more then others. The pull from the clusters of atoms, pulling all the other clusters into one another, making one very big cluster of free moving atom, spinning in space. With all the little twinkling sparks of light coming from the different atoms hitting one another, and the last cluster to come in was the first that came forth, the cluster of gas’s, that made the number one sun light up all that darkness. With the spinning, the atoms inside were being forced towards the fire, forming the hard crust just under the fire, leaving the coldness of space behind. With the two energy sources outside, one going in at a time bringing light to the center, and the other five inside, mixing up the evolution parts that came from the heat, with that to come up with the r e c i p e of life. You didn’t really think that the dinosaur came from the earth? ( did you ) How about the energy sources that became our gods? They grew up just like a baby, one day at a time. A lot of shit was going on in there, and the one outside and myself went in to help, and the number one sun just blew apart, the number one sun just wasn’t big enough to hold the endless boundaries of space, time and the six dimension of space we are. So the sun is always trying to pull the earth back into itself, because our sun is a very small part of the big bang, the number one sun. The earth came from very small parts of the number one sun when it blew up. So when the earth is going farther away from the sun, the sun is pulling the earth back to it’s self, and the light, the heat of the sun, warms up the earth, and we get to a point when the sun pulls the earth back again, to start the cycle all over again, fall, winter, spring, and summer. Summer happens, because the sun is slowing the earth down, as we go through our orbit. For they do show it wrong in there obit, because spring is where summer should be, spring happens when the earth just starts moving away from the sun out into it’s orbit.

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