Solar Distance and Weather ```Name: Basit Status: N/A Age: N/A Location: N/A Country: N/A Date: N/A ``` Question: What is the distance of earth from sun in different months of the year? What effects does this distance make on our weather? Replies: Basit, There is a distance calculator at http://www.fourmilab.ch/cgi-bin/Solar where you determine the distance of the Earth from the Sun any day of the year, in astronomical units (AU). An AU is equivalent to the average Earth-Sun distance, approximately 93 million miles (almost 150 million km). The Earth to Sun distance is about 91 million miles during the Northern Hemisphere winter and 94.5 million miles during Northern Hemisphere summer, averaging out to about 93 million miles. The distance from the Sun does affect the weather and climate very minimally (the greater the distance from the Sun, the less radiation falls on the Earth, leading to very slightly lower temperatures), but almost insignificantly in comparison to the tilt of the Earth. The Earth's tilt results in much less radiation being received per square meter in northern Canada than in the southern United States, for instance, on the first day of Spring. The difference in heating of the different latitudes of Earth is the primary driver of Earth's weather systems; this is considerably more important than the difference in distance of the Earth from the Sun as it revolves about the Sun during a year. David R. Cook Meteorologist Climate Research Section Environmental Science Division Argonne National Laboratory Because the orbit of Earth is not a circle, Earth is closer to the sun in certain months of the year. In fact, Earth is closest to the sun in the northern hemisphere' winter! Weather and climate are affected by so many different things, it is difficult to say just what this difference does to the weather. It does mean the southern hemisphere is closest to the sun during its summer. R. W. "Bob" Avakian Instructor Oklahoma State Univ. Inst. of Technology Click here to return to the Weather Archives

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