When to Close Your Pool

The calendar says fall; the water sets the date. Pick your state for city-by-city closing windows — and the cold-water rule that keeps spring openings painless.

Alabama Oct 12 – Nov 3
Alaska heater territory
Arizona Aug 14 – Nov 15
Arkansas Sep 30 – Oct 9
California Oct 18 – Nov 5
Colorado Sep 6 – Sep 23
Connecticut Sep 17 – Sep 18
Delaware Sep 20 – Sep 29
District of Columbia ~Oct 4
Florida Nov 14 – Dec 15
Georgia Oct 9 – Oct 27
Hawaii year-round
Idaho Aug 30 – Sep 18
Illinois Sep 13 – Sep 19
Indiana Sep 14 – Oct 6
Iowa Sep 12 – Sep 18
Kansas Sep 24 – Oct 1
Kentucky Sep 26 – Oct 2
Louisiana Oct 24 – Nov 7
Maine Aug 14 – Sep 1
Maryland Sep 20 – Oct 4
Massachusetts Sep 2 – Sep 17
Michigan Aug 21 – Sep 15
Minnesota Aug 23 – Sep 7
Mississippi Oct 11 – Oct 31
Missouri Sep 27 – Oct 2
Montana Aug 24 – Aug 30
Nebraska Sep 7 – Sep 21
Nevada Aug 31 – Oct 25
New Hampshire Sep 1 – Sep 3
New Jersey Sep 20 – Sep 28
New Mexico Sep 1 – Oct 13
New York Sep 6 – Sep 26
North Carolina Sep 25 – Oct 7
North Dakota Aug 25 – Aug 29
Ohio Sep 19 – Sep 22
Oklahoma Oct 5 – Oct 8
Oregon Aug 18 – Sep 22
Pennsylvania Sep 15 – Oct 2
Rhode Island ~Sep 17
South Carolina Oct 1 – Oct 30
South Dakota Sep 6 – Sep 11
Tennessee Sep 30 – Oct 14
Texas Oct 8 – Nov 7
Utah Sep 2 – Oct 11
Vermont Aug 30 – Sep 6
Virginia Sep 28 – Oct 6
Washington Sep 2 – Sep 5
West Virginia Sep 17 – Sep 24
Wisconsin Aug 27 – Sep 16
Wyoming Aug 24 – Sep 1

The short version

Close when the water — not the air — holds below about 60°F. Algae goes dormant in cold water, so a pool balanced and covered at that point winters clean and opens easy. Swimming may end weeks earlier; keep the pump running and the water sanitized until the cold actually arrives.

For a single answer for your town, the pool season lookup takes a ZIP code, and every city page under pool seasons pairs the dates with a month-by-month warm-enough table.

When to Close Your Pool

The short version

The other half of the year