Season geography
Across Arkansas's featured cities, typical openings spread from Apr 28 to May 12, closings from Sep 30 to Oct 9, and the unheated season runs 142–164 days depending on where you are. Elevation, coastal water, and urban heat all pull real dates around, which is exactly why a state-level answer isn't enough.
For your exact town, the pool season lookup takes a ZIP code. Opening day itself is a chemistry job — the dosing calculator turns your first test reading of the year into exact amounts.