PoolWindow

Pool season · South Carolina

Charleston Pool Season: the Year on One Bar

Last updated: July 15, 2026 · dates · water temp

Charleston's whole pool calendar, condensed: when the water warms, when it cools, and where today falls between those edges. Use the opening guide and closing guide for the step-by-step work; keep this page for the dates.

J F M A M J J A S O N D today (build date)

off-season opening window swim season closing window

Reading it takes ten seconds: 52 dots, one per week. Solid teal is Charleston's swim season; the hollow teal run before it (March 6 to March 27) is when to open; the hollow amber run after is when to close, with November 21 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.

The Charleston pool calendar

March 13open by
November 21close by
13280°F+ days
82°Fwater peak

Opening — target March 13

Target March 13; the practical window runs March 6–March 27, and the 7-day mean crosses the 61°F threshold around March 27. Cold-water starts are the cheap ones.

Full opening guide

Closing — deadline November 21

The window opens November 11 once water leaves the algae zone; the model deadline is November 21, a week ahead of the December 30 freeze normal.

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 Charleston water runs about 51°F at its winter floor and 82°F at its summer peak.

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

Estimated water temperature by month

Monthly averages of the site's water model run on Charleston's own normals — the shape of a typical year, not a forecast. The widget above shows where the current year actually sits.

Site-model seasonal water estimates for an unheated in-ground pool near Charleston City — ±5°F, see methodology.
JanFebMarAprMayJunJulAugSepOctNovDec
52°52°56°63°70°77°81°82°80°74°64°57°

Warmest water typically July–September (peaking near 82°F); heaters and covers shift any month up.

Data: NOAA 1991–2020 climate normals via Charleston City (3.3 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.