Earth Makes Closest Approach to Sun

The orbital milestone is known as perihelion, and it marks the time when the distance between the Earth and the sun is at its smallest. The event occurs every year in early January, and in 2012 it took place on January 4 at 8 p.m. EST. On average, the Earth orbits the sun at a distance of about 93 million miles (150 million kilometers). This distance is known as 1 astronomical unit (AU), and it serves as a yardstick for distances to other planets in our solar system. 

During the 2012 perihelion, the Earth was about 91.3 million miles (147 million km) from the sun, or about 0.983 AU. The Earth will reach aphelion on July 5. At that time, our planet will be about 94.5 million miles (152 million km) from the sun. The difference between the two extremes of Earth‘s orbit is just over 3 million miles (5 million km). According to NASA in January, the sun can appear to shine about 7 percent more intensely than it does in July during aphelion.
source:www.space.com