Credit: Jade Albert Studio, Inc. / Getty Images Summer birthdays are perfect for outdoor parties that are fun, affordable, and easy to plan. Simple activities like water play, picnics, or backyard movies can create memorable celebrations for kids of all ages. Prioritize safety, comfort, and age-appropriate activities to ensure everyone has a great time. Summer birthdays have all the perks. The odds of good weather are high, the kids have zero homework, and everyone is relaxed and happy.