Pool season · State index
Pennsylvania Pool Season 2026: Opening & Closing Dates by City
Last updated: July 25, 2026 · 12 cities covered
Both halves of the pool year for all 12 covered Pennsylvania cities. The median calendar runs April 29 to October 8. Every row links to a one-page season overview with the live water-temperature model; the opening and closing hubs carry the full checklists.
Pennsylvania: a moderate-season pool state| City | Open by | Close by | 80°F+ days |
|---|---|---|---|
| Allentown | Apr 29 | Oct 9 | 92 |
| Bethlehem | Apr 29 | Oct 9 | 92 |
| Erie | May 9 | Oct 7 | 51 |
| Harrisburg | May 2 | Oct 5 | 81 |
| Lancaster | Apr 27 | Oct 10 | 98 |
| Lebanon | May 1 | Oct 7 | 79 |
| Philadelphia | Apr 15 | Oct 22 | 109 |
| Pittsburgh | Apr 29 | Oct 8 | 70 |
| Reading | Apr 27 | Oct 10 | 91 |
| Scranton | May 2 | Oct 5 | 77 |
| State College | May 7 | Oct 1 | 44 |
| York | Apr 24 | Oct 11 | 107 |
What the columns mean
"Open by" is the recommended spring date — two weeks before the city's 7-day mean temperature crosses 61°F, the model's proxy for water approaching the 65°F algae-growth zone. "Close by" is the fall deadline — ten days after the water leaves that zone, capped a week ahead of the local 50% first-freeze date. "80°F+ days" counts days whose normal high reaches 80°F: the length of the true warm-swim season, and the fairest single number for comparing Pennsylvania cities against each other.
Every figure comes from each city's own NOAA 1991–2020 normals station (named in its guide's footer), so neighboring cities can legitimately differ by a few days. The season overview linked from each row adds the live water-temperature model and the full-year season bar; the state hubs above carry the step-by-step checklists.
Swim-season length across Pennsylvania
The fairest way to compare Pennsylvania cities is the number of days with 80°F+ normal highs — the practical warm-swim season. Every bar links to that city's one-page season overview with the live water model.
Pennsylvania pool climate at a glance
Philadelphia's humid summers anchor a reliable Memorial Day to Labor Day season, but the Allegheny highlands and lake-effect Erie corner run cooler with noticeably later spring warm-ups. In model terms that makes Pennsylvania a moderate-season state. The spread shows up clearly on the local pages: compare Philadelphia's pool season with Harrisburg's and the difference is measured in weeks, not days. Neighbors in the index run on their own normals too — see Oregon and Rhode Island for the adjacent calendars.
Pennsylvania pool season FAQ
When do pools open in Pennsylvania?
Model openings in Pennsylvania run from April 15 in Philadelphia to May 9 in Erie, with the statewide median on April 29. Each date is two weeks before that city's 7-day mean temperature crosses 61°F — early enough to start up in algae-cold water.
When should you close a pool in Pennsylvania?
The median Pennsylvania closing deadline is October 9, and every city's own deadline is capped a week ahead of its NOAA 50% first-freeze date. Closing late and cold beats closing early and warm — cool water holds its winter chemistry far better.
Which Pennsylvania city has the longest swim season?
Philadelphia leads with 109 days of 80°F+ highs per year, while State College brings up the rear at 44 days. The chart above ranks every covered city by the same metric.