You may not think that answering the question “What is a heat dome” has anything to do with the Internet, but here’s why it does: With this incredible, massive, near-national heat wave, news outlets across the country are throwing out the term ‘heat dome’, and people are taking to the Internet to find out just what the heck a ‘heat dome’ is, and it’s nearly impossible to find a site that will tell you what is a heat dome! So, here we are, filling that void on the Internet, and telling you what a heat dome is.