There are two main reasons you would want to tone and define your leg muscles to get ready for summer.
The first, of course, is so you can look great strutting around in your swimsuit all season.
The other is so you will have no problems trudging through the sand on all those long walks on the beach. Try these exercises to help define your leg muscles.
Stand with your feet a little wider than shoulder width apart. Holding your arms out in front of you and keeping your posture straight, bend at the knees until you are at an almost sitting position. Hold that pose for a five seconds and then use your legs to straighten back up. Repeat ten times, three repetitions in total.
Leaning your back against a wall, place your feet about two feet in front of you at about shoulder width apart. With your arms either out in front of you or straight down on the wall for extra support, bend at the knees until you are as close to a sitting position as you can get. Hold for five seconds and then use your legs to straighten back up to a standing position. Repeat the action ten times, three repetitions in total.