Pool season · Pennsylvania
Lebanon Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
One bar, one year, one Lebanon 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.
Lebanon, PA — 79 swim days a yearThe bar compresses Lebanon's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the April 24–May 15 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends October 7. Wherever the today marker sits, the nearest color change is your next appointment.
The Lebanon pool calendar
Opening — target May 1
Open by May 1 — a two-week head start on the May 15 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline October 7
Hold the cover until September 27, then winterize by October 7, a week ahead of the October 25 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
Monthly averages of the site's water model run on Lebanon'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° | 36° | 46° | 57° | 66° | 73° | 74° | 70° | 60° | 48° | 38° |
The curve peaks near 74°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Lancaster's pool season and Philadelphia's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Pennsylvania season index.
Lebanon pool season FAQ
When should I open my pool in Lebanon, PA?
The site model recommends opening by May 1 — about two weeks before Lebanon'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 Lebanon opening guide.
When should I close my pool in Lebanon?
Winterize by October 7. The model holds the deadline a week ahead of Lebanon's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Lebanon closing guide.
How long is the swim season in Lebanon?
Lebanon averages 79 days a year with normal highs of 80°F or better — right on the statewide median. The Pennsylvania season index ranks all 12 covered cities by the same metric.
How warm does pool water get in Lebanon?
An unheated pool near Lebanon typically peaks around 74°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 Lebanon hits the closing window
Data: NOAA 1991–2020 climate normals via Lebanon 2 W (2.4 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.