Ohio Pool Season: Opening & Closing Dates by City

Local dates for every featured Ohio city — when the water warms up, when it cools off, and how long the season actually lasts.

City Opening window Closing window Season
Columbus May 13 – Jun 3 Sep 8 – Sep 26 ≈ 118 days
Cleveland May 20 – Jun 9 Sep 9 – Sep 28 ≈ 113 days
Cincinnati May 9 – May 30 Sep 14 – Sep 30 ≈ 126 days

Windows show the stretch when each city's daily average passes through the low-to-mid 60s°F (1991–2020 NOAA records, nearest station to each city). Click a city for its month-by-month table and full season notes.

Season geography

Across Ohio's featured cities, typical openings spread from May 19 to May 30, closings from Sep 19 to Sep 22, and the unheated season runs 113–126 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.

Ohio planning pages

When to open — Ohio When to close — Ohio All states →