What's Behind The Record Heat?

Heat is beating records around the country: the first five months of 2012 have been the hottest on record in the contiguous United States. And that's not including June, when 164 all-time high temperature records were tied or broken around the country, according to government records. That's unusual, since the most intense heat usually comes in July and August for much of the country, said Jake Crouch, a climate scientist with National Climatic Data Center. For example, only 47 all-time high records were tied or broken in June of last year. http://news.yahoo.com/whats-behind-record-heat-125603530.html