At preschool, we made a water table frame using PVC piping and set a under bed storage container in it so it was long and shallow. The kids used this every single day when it was warm enough. We’d change up what went in but everyone from 2-5 loved it. Fill-up spray bottles and let them spray each other with them. Give them a container of water and a paint brush and have them paint the sidewalk or driveway.
If you buy gallon milk jugs, u can fill with water, freeze and then while frozen, poke holes all around them, and hang in a tree. They will drip and shower down as they melt. Just make sure u place them in a spot it won’t get real muddy under their feet.