It depends on what you mean by "swimming." If you mean fully immersing yourself in the water and doing laps, probably not. If you mean the kids, in swimsuits, playing in knee-deep water, being chased by the small waves and building sandcastles, then yes. If you're coming from Iowa, it will seem very nice.
Regardless, wear the swimsuits to the beach even if you think the kids won't want to get in the water. Because if you don't, they'll likely get wet anyway, with clothes on!
I was at the Hotel Del Coronado in January a couple years ago on a rainy weekend and sure enough, there were teens in the water.
PHXscuba