North America In the United States, "Cool for the Summer" debuted at number 36 on the
Billboard Hot 100 dated July 18, 2015, with opening sales of 80,000 copies. In its second week on the chart, the song rose to number 28, becoming Lovato's first top-thirty hit since "
Really Don't Care" (2014). In the same week, the song was also ranked at number 15 on
Digital Songs with sales of 108,000; and at number 40 on
Radio Songs, prompted by a 29-percent increase in the radio audience that week to 36 million. The release of its
lyric video on July 7, 2015, also prompted a gain of 185 percent in US streams to 2.4 million, the second-largest advance on the chart that week behind
Fetty Wap's song "
679". On the August 1, 2015, chart, the song slipped from its number 28 high to number 31 on the Hot 100 but continued to gain radio audience and streams. It climbed from number 40 to number 25 on Radio Songs—45 million, up 25 percent—and debuted on
Streaming Songs at number 41 with 3.3 million US streams, up 41 percent. After the released of the music video on July 23, 2015, "Cool For the Summer" rose from number 31 to number 24 on August 8, 2015, becoming Lovato's highest charting position since "
Heart Attack" (2013). The song climbed from 24 to number 19 on the Hot 100 chart issued on August 15, 2015, and from number 18 to number 12 on the Digital Songs chart with sales of 63,000 downloads (up 17 percent) in the week ending July 30, according to
Nielsen SoundScan. It climbed from number 31 to number 18 on Streaming Songs—6.6 million US streams, up 49 percent—and rose from number 22 to number 18 on Radio Songs with 56 million audience impressions, a rise of nine percent. "Cool for the Summer" later peaked at number 11 on the Hot 100. On September 23, 2016, "Cool for the Summer" was certified Double Platinum by the
Recording Industry Association of America (RIAA), denoting sales and streams of two million copies in the US. On the
Canadian Hot 100, the single entered the chart at number 50, peaked at number 14, , "Cool for the Summer" has sold over 995,000 digital downloads in the United States.
Europe and Australia In the United Kingdom, "Cool for the Summer" debuted and peaked at number seven on the
UK Singles Chart, equalling Lovato's song "
Skyscraper" to become her third-highest entry in the UK. "Cool for the Summer" was certified silver by the
British Phonographic Industry (BPI) on November 13, 2015, for sales of 200,000 copies in the UK. In Scotland, it peaked at number three. The song peaked at number 52 in Italy and received a gold certification for 25,000 copies sold in the country. "Cool for the Summer" reached number one in Greece. "Cool for the Summer" also reached the top twenty in several other European countries, including Ireland where it reached number 18. In Spain the song reached number 66 and spent 6 weeks on the chart. The song debuted at number 99 in Sweden on August 7, 2015, and reached number 63, selling 20,000 copies and being certified gold. On the
New Zealand Singles Chart, "Cool for the Summer" debuted at number 37 on July 27, 2015; it peaked at number nine, becoming Lovato's fourth top-ten single in New Zealand, and spent 14 weeks on the chart. It was certified gold by
Recorded Music NZ (RMNZ) in 2015 for selling 15,000 digital copies. On the
ARIA Singles Chart in Australia, the song debuted at number 56 and peaked at number 20, ==Music videos==