Not all heat waves are the same. Some have high humidity. Others do not. Some last for a week or more. Others last only a few days. Heat wave temperatures will be much hotter in a region that is usually hot than in a region that is usually cool. read more
A lack of winds in the upper atmosphere means that it can take a long time for the heat wave to dissipate. A 2011 study from the National Oceanic and Atmospheric Administration attributes a large increase in the probability of heat waves to the effects of global warming. read more
Heat waves are generally the result of trapped air. During the 2012 heat wave, air was trapped above much of North America for a long period of time. read more