1) Summer clothes: If you keep your seasonal clothes out of your regular dressing area, it's time to swap the sweaters for shorts and tanks. When you do this, try clothes on to make sure they still fit comfortably and are a style you still want to wear. You'll have a better idea of what items you may need to purchase for the season.
2) Check your beauty products: Not only should you check the expiration dates on your sunblock and bug spray, but you may also want to check your make-up (if you wear any). If your skin tone is anything like mine, you get a bit tan in the summer. That means my cover-up/foundation/powder changes. When I swap these out (once I've finally gotten some color on my face!), I check the consistency, smell and date on the package.
3) Clean and make accessible summer kitchen items: Items for picnics, eating on the patio, taking snacks to the park/pool/beach and so on may have been in storage for quite a few months. Rinse out any dust and set them near the front of your cabinet.
4) Check outdoor toys: Do you have bubbles, chalk, bike pump and basketball hoop at the ready? Peruse the garage or shed to dust off toys and tools for the yard. Check the air in balls and tires.
5) Enjoy yourself. In the Midwest, these summer months seem to rush by much more quickly than the snowy, wet months. Put on those shorts and sunblock, and hit the beach with your picnic basket!