Pool season · State index
Massachusetts Pool Season 2026: Opening & Closing Dates by City
Last updated: July 25, 2026 · 14 cities covered
Both halves of the pool year for all 14 covered Massachusetts cities. The median calendar runs May 12 to October 3. Every row links to a one-page season overview with the live water-temperature model; the opening and closing hubs carry the full checklists.
Massachusetts: a moderate-season pool state| City | Open by | Close by | 80°F+ days |
|---|---|---|---|
| Boston | May 10 | Oct 6 | 76 |
| Brockton | May 11 | Oct 5 | 73 |
| Cambridge | May 10 | Oct 6 | 76 |
| Fall River | May 18 | Oct 2 | 59 |
| Lawrence | May 10 | Oct 6 | 66 |
| Leominster | May 13 | Sep 30 | 68 |
| Lowell | May 15 | Oct 2 | 78 |
| Lynn | May 23 | Sep 30 | 30 |
| New Bedford | May 18 | Oct 2 | 59 |
| Newton | May 10 | Oct 6 | 76 |
| Quincy | May 16 | Oct 4 | 50 |
| Somerville | May 12 | Oct 8 | 54 |
| Springfield | May 10 | Oct 1 | 78 |
| Worcester | May 19 | Sep 28 | 15 |
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 Massachusetts 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 Massachusetts
The fairest way to compare Massachusetts 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.
Massachusetts pool climate at a glance
Chilly Atlantic springs slow warm-ups, especially on the Cape and Islands, so Massachusetts pools cluster into a mid-June to Labor Day core despite hot midsummer stretches. In model terms that makes Massachusetts a moderate-season state. The spread shows up clearly on the local pages: compare Lowell's pool season with Lawrence's and the difference is measured in weeks, not days. Neighbors in the index run on their own normals too — see Maryland and Michigan for the adjacent calendars.
Massachusetts pool season FAQ
When do pools open in Massachusetts?
Model openings in Massachusetts run from May 10 in Boston to May 23 in Lynn, with the statewide median on May 13. 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 Massachusetts?
The median Massachusetts closing deadline is October 4, 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 Massachusetts city has the longest swim season?
Lowell leads with 78 days of 80°F+ highs per year, while Worcester brings up the rear at 15 days. The chart above ranks every covered city by the same metric.