Kim Davie remembers her reaction when her mom suggested she and twin sister Shayla enroll in a summer online course after their freshman year.

"I wasn't all for it," she says sheepishly.

A year later, though, both Houston-area high schoolers are willingly returning for another summer with the International Connections Academy to get a head start on next fall's course material. Shayla will take statistics after enrolling in Algebra 2 a year ago. Kimberly will study physics after last year's geometry course. Both expect a similar summer as​ last year, when they still had time for cheerleading camp, fitness camp and a vacation to Mexico.

"You could still work the class into your schedule," Kim says. "Any free time you had, you could use it."

[Consider taking online college courses in high school.]

Whether the goal is getting a head start like the Davie sisters, tackling advanced subjects, preparing for college entrance exams or even retaking difficult classes, summer provides an unique opportunity forcollege-bound high schoolers to use​ online learning options.

"You might be traveling or you might be doing a summer enrichment program, things like that," says Michael Boothroyd, Kaplan Test Prep's executive director of SAT and ACT programs. ​"So online programs obviously travel with you."

And students have plenty of choices. Of the 75 percent of school districts nationwide which offer some sort of online or blended courses, the vast majority do so during the summer months, says Susan Patrick, president and CEO of the International Association for K-12 Online Learning.​ Then there are more than two dozen states with statewide virtual schools, ​programs run by private companies like Connections,​ and a stable of traditional college test-prep companies like Kaplan that have moved​ their services online.

"I think it's really important for students to determine the goal of why they want to enroll in a summer school class," Patrick says. Students considering an online course should also find out what the cost may be – even some public school systems charge a fee – as well as the format of a given course and an instructor's involvement, she says.

Class format can vary quite widely, and in some cases could conflict with other summer plans.​

With the International Connections Academy, the Davies sisters estimate they spend two hours a day studying. But at programs designed specifically for high-performing or gifted students, like theAccelerated Summer Option through Northwestern University's Center for Talent Development, students can spend as much as six hours a day on compact nine-week honors and Advanced Placement courses.

[Discover the keys to success in advanced placement courses.]

Eric Calvert, the Center for Talent Development's associate director, ​says the program generally isn't a good fit for students looking to wedge summer learning into the margins of a busy schedule that may include vacations, camps or other enrichment opportunities. That's not often an issue, though, because such programs typically draw enthused students who have prioritized the program, Calvert says.​

Conversely, students looking for online help preparing for the SAT and ACT may not even choose to enroll in a class, but rather use free online practice exams and video tutorials at their disposal whenever their summer schedule allows. taken by/usnews.com