Pool season · Pennsylvania
Allentown Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
One bar, one year, one Allentown 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.
Allentown, PA — 92 swim days a yearReading it takes ten seconds: 52 dots, one per week. Solid teal is Allentown's swim season; the hollow teal run before it (April 22 to May 13) is when to open; the hollow amber run after is when to close, with October 9 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.
The Allentown pool calendar
Opening — target April 29
Open by April 29 — a two-week head start on the May 13 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline October 9
The window opens September 29 once water leaves the algae zone; the model deadline is October 9, a week ahead of the October 24 freeze normal.
Estimated water temperature by month
This is Allentown's typical-year water curve: the same EWMA model as the live widget, run on the 1991–2020 normals instead of this week's weather.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 32° | 30° | 37° | 47° | 58° | 67° | 74° | 75° | 70° | 60° | 49° | 39° |
The curve peaks near 76°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with York's pool season and Bethlehem's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Pennsylvania season index.
Allentown pool season FAQ
When should I open my pool in Allentown, PA?
The site model recommends opening by April 29 — about two weeks before Allentown'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 Allentown opening guide.
When should I close my pool in Allentown?
Winterize by October 9. The model holds the deadline a week ahead of Allentown's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Allentown closing guide.
How long is the swim season in Allentown?
Allentown averages 92 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 Allentown?
An unheated pool near Allentown typically peaks around 76°F in high summer and bottoms out near 30°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 Allentown hits the closing window
Data: NOAA 1991–2020 climate normals via Allentown International Airport (4.0 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.