Towson University student Christelle Etienne isn’t whiling away these long, lazy days of summer lounging by the pool or hanging out with friends from high school.

Instead, she’s sitting in a classroom at Montgomery College in suburban Maryland taking ­classes in anatomy and physiology.

A pre-nursing and foreign language major with a double minor, Etienne hopes the extra work will keep her on schedule to earn her bachelor’s degree.

That’s something only 42 percent of first-time, full-time college students manage to do, according to the Education Department. And the longer students take to finish, the more they wind up paying.

More students have started to forgo long summer breaks to cut costs and to stay on track for graduation. Since many four-year institutions largely shut down between May and late August, reflecting an academic calendar that predates the industrial era, many students are going to community colleges.

Listening to lectures and slogging through schoolwork in the summer “is no joke,” Etienne said. “But there are so many classes I have to take.”

This phenomenon has grown so much it has a name: summer swirl. There’s been a steady increase in summer swirlers anxious to speed up their progress to graduation, according to the National Student Clearinghouse Research Center, a nonprofit that tracks the phenomenon. They are also more likely to graduate from their home institutions than are classmates who don’t take summer classes, the group found.

Community colleges are thrilled for the extra business. Their enrollment has declined by 27 percent, or nearly 2 million students, since 2010, the clearinghouse reports. Many colleges are promoting their summer programs. “Success Doesn’t Stop with Summer,” proclaims Suffolk County Community College in New York, over a photo of a bespectacled professor holding class outdoors. “It’s affordable! It’s easy! It’s flexible! It’s smart!” declares Raritan Valley Community College in New Jersey. Montgomery College has also launched a campaign to draw more visiting students and has a dedicated Web page for them.

Changes to federal financial aid have made summer classes more accessible. Since last year, students have been able to use federal Pell Grants for summer study; those who do so get an average of $1,500, according to the National Summer Learning Association.

Despite these changes, students who want to graduate as quickly as possible still bump up against the traditional schedule. The nine-month academic calendar dates to agrarian times, when students were needed to help with planting and harvesting, said Ken Smith, vice provost for academic resource management at Virginia Tech, a four-year university that has two summer sessions.

Smith pointed to institutions that considered changing this, such as Purdue University, which announced in 2012 it would switch to what it called a “balanced trimester” plan, with a full slate of summer courses. That never happened because it would have required rewriting traditional nine-month faculty contracts and figuring out how faculty would be paid in the summer, a Purdue representative said. At the time, the federal government also limited Pell Grants to two terms per year.

The average number of courses offered at four-year campuses in the summer actually fell between 2014 and 2017, the last period for which the figures are available, according to a survey by the Association of University Summer Sessions. Those universities and colleges that responded to the survey offered an average of 766 summer courses, although more than a third of these were online or parts of study-abroad programs.

In the future, four-year public universities may add more classes, largely because schools are under pressure from legislatures and others to use facilities year-round, said Rachel Miller, who directs summer programs at the University of Virginia and serves as president of the association.

“We are seeing a push, especially for state institutions, to justify having the lights on and the buildings occupied during the summer,” Miller said.

For now, community colleges are often the only choice for students at four-year institutions that don’t offer the summer classes they need.

Sanaa Mironov took off most of last year from her studies at the University of Maryland Baltimore County (UMBC) when she had a baby. She’s catching up by taking math and science classes this summer at Montgomery College, where she already plans to take two physics courses next summer.

“It’s reducing the amount of time that I have to take to complete my degree, and it’s also helping me financially, since I’m paying everything out of pocket,” she said.

For a four-credit class during the summer at UMBC, Mironov would have paid $1,560 in resident tuition. The same class at Montgomery College costs about $690. The community college is also closer to her home.

UMBC offers summer courses — about 400, compared with more than 1,000 at Montgomery College.

Thirty years ago, students might have taken “fun” classes during the summer, “but nowadays we’re very aware that students have a lot on their plates, and they are going to take classes that advance them toward graduation,” said Beth Snyder Jones, UMBC’s associate vice provost for summer, winter and special programs.

Students also take summer classes at community colleges when they have demanding majors with a lot of required courses. John Brymer, a chemistry major with a prepharmacy minor at James Madison University in Harrisonburg, Va., realized in the spring he would need to do that if he wanted to graduate on time.

“You have a certain amount of prerequisites that you need to knock out just in general education before you apply for pharmacy school,” said Brymer, who is attending Northern Virginia Community College this summer. “I don’t know where I would fit these two classes in, if not the summer.”

Taylor Harris is an undergraduate at Hampton University in Virginia, where she’s enrolled in a five-year bachelor’s-master’s program in architecture. Because architecture classes require a lot of studio time working on projects, she decided to take physics at Montgomery in the summer to lighten her load in the fall.

“It makes my schedule more manageable,” Harris said.

Whether those credits transfer to students’ four-year institutions is up to them to figure out. Generally, students who transfer lose more than 40 percent of the credits they earned and paid for, according to the Government Accountability Office. That figure, from a 2017 report that is the most recent available on the topic, accounts for all transfer students.

Summer swirlers have some protections against this. Montgomery requires visiting students to have their home institutions submit a “permission to enroll” form. This not only exempts them from having to submit transcripts or take placement tests, but it also ensures their credits will be accepted.

“They get the information from their home institution that says, ‘Yes, this student can take this course at your institution, and it will be transferred back,’ ” said Jamin Bartolomeo, Montgomery’s dean of student access.

Northern Virginia Community College sends students course content summaries to submit to their schools so they can get advance approval for classes they intend to take.

Community colleges also have more experience accommodating students with nontraditional enrollment patterns and schedules than their four-year peers.

“One of our major tenets is to be available and to offer access to all students,” said Keri Bowman, director of academic planning and advising at Northern Virginia Community College. “Sometimes the focus on access and availability is less of a concern for four-year institutions.”

This story about community college summer classes was produced by The Hechinger Report, a nonprofit, independent news organization focused on inequality and innovation in education. Sign up for our higher education newsletter.