Searing temperatures in the Northeast and Midwest likely helped fuel the boom, along with Independence Day newcomer 'The First Purge.'

There were major fireworks at the July Fourth box office this year as revenue reached its highest level in five years, including an uptick of 29 percent over 2017. Searing temperatures in the Northeast and Midwest were no doubt a factor in the stronger-than-usual showing. On Wednesday, heat advisories and heat warnings affected more than 94 million people. Independence Day is historically a mixed bag when it comes to moviegoing, with many consumers otherwise occupied. It also helped that Universal decided to open The First Purge on Wednesday.