Reading to your child not only helps him learn to read but also exposes him to ideas that he may not otherwise experience. Weekly, choose a few books that relate to summer activities such as swimming, having picnics, camping or spending a day at the beach. Have your child practice tracing over words relating to the book, and then draw pictures that pertain to the story.
Fill three ice-cube trays with water, and dye the water in one tray blue, one red and the other yellow. Freeze the trays. Pull them out and let one ice cube melt in clear glasses so your child can see the colors. Start combining colors to see what the results will be. Finally, let your child combine ice cubes herself and experiment with multicolor results. Another water experiment simply involves letting your child spray an exterior wall or patio with water. Let her watch the water evaporate and help her figure out why this happens.
Talk about summertime holidays, such as Father's Day and the Fourth of July, and have your child create crafts or participate in activities that relate to the holidays. If your family's heritage stems to another country, teach your child about those holidays, too, and talk about why not everybody celebrates every holiday. Celebrate a holiday -- perhaps the Fourth of July -- and ask your child what people do on that holiday after she's had time to observe her surroundings. (In this case, the answer would be to have a picnic and watch fireworks displays).
Visit a farmer's market to see what fruits and vegetables are in season in your area. Let your child pick out a few produce items to try at home. Discuss different ways to prepare in-season produce and let your child help. Your child may want to sample the veggies raw with a homemade dip, or add them to her favorite pasta dish or pizza. Add to the education by preparing paper cutouts of foods from all the food groups and let your preschooler choose foods to make a complete meal. The child will learn about nutrition and be able to laugh at some unusual food combinations she creates.