Want to join a gym? Summer may have best prices

Tempting as it may be to take a jog in the park or join an outdoor boot camp, there's good reason to check out the gym this summer—it may be your cheapest shot at membership year-round.

Sure, there are plenty of promotions in January, as gyms compete for their share of New Year's resolution-makers. But there are also plenty in the summer, as gyms try to lure in new members amid sunshine, fresh air and warm weather.

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According to the International Health, Racquet & Sportsclub Association, new memberships hit a low point from June through August. (The exceptions: Clubs that have a pool or tennis courts, and those in areas with warm weather all throughout the year.)

Although the average monthly rate for gym fees is $49, per the IHRSA, prices can be much higher—or lower. "You also see other gyms popping up where it's a low cost of entry, and there are no frills," said VJ Mayor, vice president of communications and research for the Sports and Fitness Industry Association. At some, memberships start at $15 or $20.

Check out the video for some tricks to slim gym fees. One to consider: Be a free agent when it comes to your fitness.

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Popular fitness club activities

Men Prefer
Women Prefer
Bootcamp 7% 8%
Free weights (barbells) 30% 14%
Free weights (dumbbells) 38% 21%
Pilates 3% 11%
Running 35% 34%
Group cycling 10% 11%
Treadmill 34% 42%
Weight/resistance machines 42% 33%
Yoga 11% 26%
SOURCE: International Health, Racquet & Sportsclub Association

Common fitness club programs

Facilities offering it
Personal training 93.27%
Step/bench aerobics 85.63%
Strength training 81.87%
Yoga 78.51%
Group cycling 67.23%
Kickboxing 47.31%
Pilates 44.22%
Aquatic exercise 42.93%
Dance 39.51%
Outdoor boot camp 37.77%
Martial arts 26.66%
Walking classes 10.83%
Group running 7.69%
Gymnastics 5.56%
SOURCE: International Health, Racquet & Sportsclub Association

By IHRSA's figures, of the 62.1 million Americans who used a health club last year, 9.2 million weren't members. Taking advantage of free trials and low-cost passes can keep costs low, and offer the ability to switch up exercise routines and work in more fun free summer activities like running or hiking.

For $85, the American Health and Fitness Alliance sells books of passes for fitness clubs in New York, Chicago, Houston and Los Angeles. And daily deal websites offer multiclass packages and one-month gym trials for as much as 85 percent off the going rate.

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Hopping around to try different gyms can also be helpful when it comes to picking the right one to commit to, said Mayor. Attendance rates tend to drop if a gym is more than 10 minutes from where a member lives. (See charts above for some of the most popular gym features and programs.)

Trial visits can also help you figure out how well a gym's value matches its price—Are you using all it its pricey amenities? Do crowds shut you out of popular classes? How often is the equipment out of order? "Make sure it's a gym that you're actually going to use," he said.

—By CNBC's Kelli B. Grant.