One of the fun parts of summer is enjoying daylight longer. A fun activity you can do with children is point out this phenomenon daily. Here is one way to do it.
Pick a daylight time today and go outside and see how light it is. Then pick the same time each evening and talk about how light it seems. No matter what time you pick, you and your child will notice the the brightness for a particular time will begin to fade. Before long a time that was definite daylight in the summer will be darker in the fall.
If you end up doing your check daily, this change will be gradual. If you end up checking weekly or even less than that you will notice the changes will come in a more dramatic way.
Summer solstice, summer fun, summer education too! Enhance this concept for your children with whatever knowledge you have about the rotating angle of the sun as it shines on the earth and with whatever else you would like to share about the changing seasons.