Summer school is no longer just for students who are required to enroll in remedial education.

National and local advocates say the hot months — which for many conjure images of beaches, pools and lazy days — exacerbate the achievement gap and lead to significant “summer brain drain,” with students losing academic skills while away from school.

So families are enrolling their children in academic-focused summer programs to stay on track or get ahead for the coming school year.

National Summer Learning Day —an advocacy day celebrated last Wednesday — emphasizes the importance of keeping children learning during the long summer break. In 2009, experts from Johns Hopkins University determined that, regardless of family income or background, students lose more than two months of the math computational skills they learned during the academic year. In reading, students from low-income homes lose as much as three months of their skills, while middle-class students make slight gains.

In the District, more than 2,700 students in kindergarten through the seventh grade participate in the public school system’s free summer programs at nine schools. And even more participate in other free, academic-focused summer programs run by nonprofits, charter schools and other organizations.

“We know that these summer months are some of the most important months of the year for our young people,” first lady Michelle Obama said in a video message commemorating National Summer Learning Day. “In fact, research shows that if kids take a break from learning all summer, they not only miss out on new information and skills, they can actually lose up to three months’ worth of knowledge from the previous year.”

Brittany McAllister, a third-grade math teacher at Seaton Elementary School in Shaw, also serves as a summer school teacher at Power Scholars Academy — a six-week summer program at Seaton Elementary hosted by the YMCA in collaboration with the nonprofit BELL organization. About 90 percent of the 130 students enrolled in the summer academy attend Seaton during the academic year.

McAllister said that rounding numbers is one of the hardest math concepts for third-graders to grasp. Students who attend the summer program typically have a much easier time during the school year understanding rounding than those who don’t, she said.

“The students had retained what they learned over the summer, and we’re able to carry it into the school year,” McAllister said.

About 5,000 students throughout the country are enrolled in a Power Scholars Academy. There are two academies in the District, the one at Seaton and another at nearby Cleveland Elementary School. Taught by certified teachers, the programs include 90 minutes each of math and reading instruction each day. The afternoon is filled with science courses and extracurricular activities, including music, drama, leadership development and fitness.

“I like to play the drums,” said 7-year-old Christian Nanton, a rising second-grader who attends the program at Seaton. “I’ve been banging on things since I’ve been born.”

Janice Williams, the senior vice president of program development at the YMCA of Metropolitan Washington, said parents rush to sign up their children in the summer programs each year. Enriching options for students in the summer can be expensive, and these programs provide free supervision for children while also giving them meaningful academic experiences.

The children also look forward to the summer program, Williams said, asking their teachers during the academic year when their parents can enroll them.

“If we can maintain that kind of excitement in our young people, then we will not have the problem of students dropping out,” Williams said. “All of these scholars know they are going to college.”

To combat the “summer brain drain,” many D.C. charter and public schools offer extended school years so students have shorter summer breaks. In February, D.C. Public Schools (DCPS) announced that nearly 4,000 students at schools in some of the city’s poorest neighborhoods would move to extended-year schedules next fall. So instead of a long summer break, students would have more frequent breaks during a school year that runs 200 days across 12 months.

For older children this summer, the city’s public school system is offering an enrichment program for 100 students in fifth through eighth grades at three schools.

“This is the first year that the summer enrichment program has been held east of the Anacostia River to ensure even more equal access,” said Michelle Lerner, a schools spokeswoman. “The DCPS summer enrichment program is unique because students help design their learning experience in mini-courses that explore topics such as forensic science, theater production, ancient civilizations and mythology.”