https://www.livestrong.com/article/13712683–summer-exercise-burns-most-calories/

Whether you’ve been hibernating this past winter or confined to indoor workouts, this summer season has the remedy to your cabin fever. From water sports to games in the sand, there are a host of outdoor activities that are not only fun, but that also burn calories and strengthens the body from head to toe! So if you’re looking to stay fit this summer, there’s no need to hit the gym — just try one (or all) of these seven activities.

With each activity listed, the calories burned are based on calculations of from LIVESTRONG.COM’s MyPlate, which factors in body weight in pounds (125 pounds/150 pounds/225 pounds) for one hour of activity. Or to find out your specific caloric expenditure, download MyPlate.

1. Kayaking
A sightseeing tour by kayak is a fun way to explore your summertime surroundings. Paddling at a pace of just two miles per hour will burn more than 200 calories for each hour you’re on the water. Plus, kayaking targets the muscles of your upper body, core and back.
To propel the boat forward (and to effectively burn calories), REI’s Intro to Kayaking guide suggests that you rotate your torso to the side as the blade moves behind you. Follow the blade with your eyes and your torso will follow. Focus, too, on pushing against the shaft with your upper hand as you move.

Calories Burned: 283/352/510

2. Biking
Grab your helmet and discover new places! Biking is a great way to sightsee and enjoy the summer breeze while cycling as leisurely or as intensely as you like. This outdoor activity burns calories, tones legs and strengthens the lungs. Take some friends along with you, pick a new destination you want to discover and even pack a healthy lunch for an impromptu picnic.
A good, neutral riding position starts with the head and goes all the way to your feet. Relax your neck and lower your shoulders away from your ears, bend your elbows and make sure your knees are tracking over the balls of your feed/pedals. If your knees are bowing out to the side when you ride, it may look a little funny and can definitely cause pain and/or injury.

Calories Burned: 312/381/408 (10 mph, moderate)

3. Rock Climbing
Heights aren’t everyone’s cup of tea, but if you’re up for a challenge and a great workout, add rock climbing to your summer bucket list. Rock climbing builds full-body strength and improves coordination, and it’s also a great way to train many of your body’s underworked muscles, such as your back, shoulders and the muscles in your hand (for grip).
Whether you’re climbing indoors or outdoors, to maximize your experience, Christian Helger, a certified rock climbing instructor at Acadia Mountain Guides Climbing School in Maine, recommends wearing comfortable athletic wear and removing any rings from your fingers.

When you’re climbing, you’re constantly using your back muscles, so Christian also recommends finding good food holds so you can push off with your legs more than you pull up with your arms. It’s more efficient, since generally your legs are generally much stronger than your arms.
Calories Burned: 624/773/1,123

4. Standup Paddleboarding
A popular summertime activity, paddleboarding will test your balance skills and engage your core. But because the technique to paddling likely isn’t something you do every day, it’s best to research local paddleboarding group classes where a trained instructor will teach safety tips and techniques for the best experience.
To help maximize your SUP workout — and minimize your chances of falling off — REI’s Stand Up Paddle Boarding Basics says: “Position your feet so they are parallel, about hip-width distance apart and centered between the edges of the board. Keep your toes pointed forward, knees slightly bent and your back straight. Make sure to keep your head and shoulders steady and upright, and shift your weight by moving your hips. Your gaze should be level at the horizon. Avoid staring at your feet.”
Calories Burned: 358/444/644
Read more: 12 Amazing Paddleboard Yoga Poses (and How to Do Them)

5. Swimming
A refreshing way to torch calories, swimming is a great activity to dive into this summer. Plus, it’s a great option for those who may suffer from knee or lower-back pain because it’s considered a nonimpact sport. The water gives you buoyancy, so you’ll float through your session without putting pressure on your joints.
To get the most from your swimming session, proper form is key! Keep your head in line with your torso and look straight down toward the bottom of the pool, Christophe Keller, triathlete and founder of Enjoy Swimming writes on his site. Don’t look forward, as that can lead to your hips and legs dropping and you’ll have to kick harder to keep them up. And while swimming can be a solo sport, the Red Cross advises people to always have a swim buddy, as there’s safety in numbers.
Calories Burned: 397/492/714 (light, moderate freestyle)

6. Snorkeling
With or without fins, snorkeling is a total-body workout that can torch calories quickly while taking it easy on your joints. “Like many water-based exercises, snorkeling has the added benefit of providing healthy exercise to those with joint pain, stiffness and even injuries because it’s considered a low-impact sport,” says Mike Hearron, physical therapist at ATI Physical Therapy.
Every underwater movement you make, whether with your arms, legs or back, forces your muscles to push against the water. The resistance is heightened if you decide to wear fins, as the increased surface area provides more resistance against the water. As you dive down, you’re forced to kick harder, burning more calories. But to prevent tiring out early, don’t kick too hard when you’re swimming forward, since even a leisurely kicking pace is enough to propel you.
Calories Burned: 283/352/578

7. Surfing
Although you probably won’t be doing any fancy tricks like surf pros, you’ll still be burning calories while having some fun. Surfing is an amazing sport that requires endurance, upper- and lower-body strength and also good flexibility, says Suzie Cooney, certified personal trainer and water sports trainer in Maui, Hawaii.
Surfing is a great workout the entire time you’re out on the water. Paddling out into the ocean and catching a wave works your upper body, while hopping up on the board and riding the waves works your core and legs (quads, hamstrings, glutes). If you catch a wave, bend your knees and don’t hunch over, writes Justin Cote for Adventure Sports Network. You have way better balance with your knees bent and absorbing the energy of the wave.
Calories Burned: 170/211/306