Pool season · State index
Maryland Pool Season 2026: Opening & Closing Dates by City
Last updated: July 25, 2026 · 9 cities covered
Both halves of the pool year for all 9 covered Maryland cities. The median calendar runs April 20 to October 16. Every row links to a one-page season overview with the live water-temperature model; the opening and closing hubs carry the full checklists.
Maryland: a moderate-season pool state| City | Open by | Close by | 80°F+ days |
|---|---|---|---|
| Baltimore | Apr 12 | Oct 24 | 110 |
| Columbia | Apr 17 | Oct 21 | 107 |
| Ellicott City | Apr 20 | Oct 15 | 89 |
| Frederick | Apr 14 | Oct 18 | 112 |
| Germantown | Apr 26 | Oct 11 | 81 |
| Hagerstown | Apr 25 | Oct 12 | 98 |
| Salisbury | Apr 13 | Oct 24 | 113 |
| Silver Spring | Apr 22 | Oct 16 | 101 |
| Waldorf | Apr 24 | Oct 12 | 88 |
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 Maryland 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 Maryland
The fairest way to compare Maryland 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.
Maryland pool climate at a glance
Chesapeake-area heat and humidity anchor a solid Memorial Day to Labor Day season, while the western Maryland mountains run cooler and shorter than the Baltimore-Washington corridor. In model terms that makes Maryland a moderate-season state. The spread shows up clearly on the local pages: compare Salisbury's pool season with Silver Spring's and the difference is measured in weeks, not days. Neighbors in the index run on their own normals too — see Maine and Massachusetts for the adjacent calendars.
Maryland pool season FAQ
When do pools open in Maryland?
Model openings in Maryland run from April 12 in Baltimore to April 26 in Germantown, with the statewide median on April 20. 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 Maryland?
The median Maryland closing deadline is October 16, 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 Maryland city has the longest swim season?
Salisbury leads with 113 days of 80°F+ highs per year, while Germantown brings up the rear at 81 days. The chart above ranks every covered city by the same metric.