Pool season · Ohio
Middletown Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
One bar, one year, one Middletown pool. The season bar below draws everything the model knows — opening window, prime season, closing window — against today's date, with the working details one click away on the opening and closing pages.
Middletown, OH — 100 swim days a yearThe bar compresses Middletown's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the April 21–May 12 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends October 8. Wherever the today marker sits, the nearest color change is your next appointment.
The Middletown pool calendar
Opening — target April 28
Open by April 28 — a two-week head start on the May 12 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline October 8
The window opens September 28 once water leaves the algae zone; the model deadline is October 8, a week ahead of the October 19 freeze normal.
Estimated water temperature by month
Monthly averages of the site's water model run on Middletown's own normals — the shape of a typical year, not a forecast. The widget above shows where the current year actually sits.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 31° | 30° | 37° | 47° | 58° | 68° | 74° | 74° | 70° | 60° | 48° | 38° |
The curve peaks near 75°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Mansfield's pool season and Newark's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Ohio season index.
Middletown pool season FAQ
When should I open my pool in Middletown, OH?
The site model recommends opening by April 28 — about two weeks before Middletown's 7-day mean temperature crosses 61°F, while the water is still too cold for algae. The step-by-step sequence is in the Middletown opening guide.
When should I close my pool in Middletown?
Winterize by October 8. The model holds the deadline a week ahead of Middletown's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Middletown closing guide.
How long is the swim season in Middletown?
Middletown averages 100 days a year with normal highs of 80°F or better — about 4 days earlier than the Ohio median. The Ohio season index ranks all 14 covered cities by the same metric.
How warm does pool water get in Middletown?
An unheated pool near Middletown typically peaks around 75°F in high summer and bottoms out near 29°F in winter, never quite reaching the 78°F comfort line without a heater or solar cover. The month-by-month curve above shows the whole cycle; the methodology page explains the ±5°F error bars.
Email me when Middletown hits the closing window
Data: NOAA 1991–2020 climate normals via Franklin (4.3 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.