PoolWindow

Pool season · South Carolina

Greenville Pool Season: the Year on One Bar

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

One bar, one year, one Greenville 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.

Courtyard swimming pool at dawn in a temperate climateGreenville, SC — 109 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

Reading it takes ten seconds: 52 dots, one per week. Solid teal is Greenville's swim season; the hollow teal run before it (March 31 to April 21) is when to open; the hollow amber run after is when to close, with October 22 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.

The Greenville pool calendar

April 7open by
October 22close by
10980°F+ days
78°Fwater peak

Opening — target April 7

Target April 7; the practical window runs March 31–April 21, and the 7-day mean crosses the 61°F threshold around April 21. Cold-water starts are the cheap ones.

Full opening guide

Closing — deadline October 22

The window opens October 12 once water leaves the algae zone; the model deadline is October 22, a week ahead of the November 7 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 Greenville water runs about 41°F at its winter floor and 78°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 Greenville's own normals — the shape of a typical year, not a forecast. The widget above shows where the current year actually sits.

30°40°50°60°70°80°90°JanFebMarAprMayJunJulAugSepOctNovDec65° algae zone58° swimmable startopen Apr 7close Oct 2278°F peak41°F floor
Site-model seasonal water estimates for an unheated in-ground pool near Greenville — ±5°F, see methodology.
JanFebMarAprMayJunJulAugSepOctNovDec
41°42°48°56°64°71°77°77°74°65°54°46°

The curve peaks near 78°F — comfortable-water months here usually involve a heater or a solar cover.

Every station tells its own story: compare this curve with Florence's pool season and Mauldin's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the South Carolina season index.

Greenville pool season FAQ

When should I open my pool in Greenville, SC?

The site model recommends opening by April 7 — about two weeks before Greenville's 7-day mean temperature crosses 61°F, while the water is still too cold for algae. The step-by-step sequence is in the Greenville opening guide.

When should I close my pool in Greenville?

Winterize by October 22. The model holds the deadline a week ahead of Greenville's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Greenville closing guide.

How long is the swim season in Greenville?

Greenville averages 109 days a year with normal highs of 80°F or better — about 10 days later than the South Carolina median. The South Carolina season index ranks all 12 covered cities by the same metric.

How warm does pool water get in Greenville?

An unheated pool near Greenville typically peaks around 78°F in high summer and bottoms out near 41°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 Greenville (0.9 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.