Maine Pool Season: Opening & Closing Dates by City

Local dates for every featured Maine city — when the water warms up, when it cools off, and how long the season actually lasts.

City Opening window Closing window Season
Portland Jun 8 – Jul 4 Aug 20 – Sep 13 ≈ 75 days
Bangor Jun 10 – Jul 8 Aug 16 – Sep 7 ≈ 66 days
Caribou Jun 18 – Jul 6 Aug 14 – Aug 26 ≈ 39 days

Windows show the stretch when each city's daily average passes through the low-to-mid 60s°F (1991–2020 NOAA records, nearest station to each city). Click a city for its month-by-month table and full season notes.

Season geography

Across Maine's featured cities, typical openings spread from Jun 19 to Jul 6, closings from Aug 14 to Sep 1, and the unheated season runs 39–75 days depending on where you are. Elevation, coastal water, and urban heat all pull real dates around, which is exactly why a state-level answer isn't enough.

For your exact town, the pool season lookup takes a ZIP code. Opening day itself is a chemistry job — the dosing calculator turns your first test reading of the year into exact amounts.

Maine planning pages

When to open — Maine When to close — Maine All states →