>> it is important. it shows you it could be worse what's going on out there. a late summer heat wave has parts of the midwest and plains states sweltering. heat advisories are in effect for seven states. let's figure out what this means. we have cnn meteorologist indra petersons on it of course tracking these high pressure systems. what does it mean? >> temperatures literally 20 degrees above normal. you add in the humidity many feel like 100 to 110 degrees. one of the first lessons of the new school year, how to beat the heat. students huddle around fans just to stay cool. water bottles, popsicles and ice are small pieces of relief. >> students brought in fans, my friend brought in ice. so we're going to pass out ice. >> we have water bottles right up there so we'll stay hydrated i think. >> it's just really hot and it's just hard because we're sweating you an all that stuff like that.