Why is it hotter in the summer months than it is in the winter months?
Often times we don't stop to think why the change in temperature happens. During the summer months, the Earth is tilted away from the Sun, making it actually further away from the Sun than it is during the winter months. The intense angle of light entry in the summer doesn't allow it to spread out as much as it is able to in the winter. Combine this with longer days and you get some serious heat!
For more information check out this Web site (Site is outside of planetSEED.com): http://www.loc.gov/rr/scitech/mysteries/seasons.html