Dive Into Summer Fun: Outdoor Pool Season Ending Soon! From cannonballs and swimming lessons to lazy afternoons floating in the sun, Sioux Falls certainly made the most of the hot summer months. End-of-Season Splash: Swimming Gone to the Dogs! While the outdoor pools are closing, summer fun isn't completely over. So if summer has flown by a little too quickly, consider this your reminder: there's still time for one more splash.