PoolWindow

Pool season · Massachusetts

Brockton Pool Season: the Year on One Bar

Last updated: July 25, 2026 · dates · water temp

One bar, one year, one Brockton 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.

Cool blue pool in a short-season northern climateBrockton, MA — 73 swim days a year
J F M A M J J A S O N D today (build date)

off-season opening window swim season closing window

The bar compresses Brockton's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the May 4–May 25 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends October 5. Wherever the today marker sits, the nearest color change is your next appointment.

The Brockton pool calendar

May 11open by
October 5close by
7380°F+ days
74°Fwater peak

Opening — target May 11

Target May 11; the practical window runs May 4–May 25, and the 7-day mean crosses the 61°F threshold around May 25. Cold-water starts are the cheap ones.

Full opening guide

Closing — deadline October 5

Hold the cover until September 25, then winterize by October 5, a week ahead of the October 19 freeze normal. Late and cold beats early and warm.

Full closing guide

Where the water sits today

SEASONAL VIEW

Estimated unheated pool water temp (site model, ±5°F). The live estimate loads in your browser from Open-Meteo air temperatures; in a typical year Brockton water runs about 29°F at its winter floor and 74°F at its summer peak.

40 45 50 55 60 65 70 75 80 85 58 open 65 algae

Estimated water temperature by month

This is Brockton'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.

20°30°40°50°60°70°80°90°JanFebMarAprMayJunJulAugSepOctNovDec65° algae zone58° swimmable startopen May 11close Oct 574°F peak29°F floor
Site-model seasonal water estimates for an unheated in-ground pool near Brockton — ±5°F, see methodology.
JanFebMarAprMayJunJulAugSepOctNovDec
32°30°35°44°54°64°72°74°69°59°48°39°

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 Boston's pool season and Cambridge's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Massachusetts season index.

Brockton pool season FAQ

When should I open my pool in Brockton, MA?

Open by May 11 — the model places Brockton's 61°F crossing about two weeks later, and every warm day you wait pushes the water toward the 65°F algae zone. The Brockton opening guide has the 12-step sequence.

When should I close my pool in Brockton?

Close by October 5: cool water keeps its winter chemistry, but freeze damage is the hard stop. The Brockton closing guide sequences the work backward from that date.

How long is the swim season in Brockton?

Brockton averages 73 days a year with normal highs of 80°F or better — right on the statewide median. The Massachusetts season index ranks all 14 covered cities by the same metric.

How warm does pool water get in Brockton?

An unheated pool near Brockton 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.

Data: NOAA 1991–2020 climate normals via Brockton (2.5 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.