PoolWindow

Pool season · Texas

Flower Mound Pool Season: the Year on One Bar

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

This is the one-page view of Flower Mound's pool year: both model windows, the estimated water-temperature curve, and today's live position on the season bar. The detailed checklists live on the opening and closing guides; this page is the calendar you check between them.

Resort pool at dusk in a hot, long-season climateFlower Mound, TX — 157 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

Each dot on the bar is one week of Flower Mound's typical year, colored by what the model says that week is for: gray weeks are off-season, hollow teal marks the opening window (March 11–April 1), solid teal is swim season, and hollow amber is the closing window ending November 9. The black marker is today — its position against the colors is the entire executive summary.

The Flower Mound pool calendar

March 18open by
November 9close by
15780°F+ days
86°Fwater peak

Opening — target March 18

Open by March 18 — a two-week head start on the April 1 crossing keeps startup chemistry small and beats the local service rush.

Full opening guide

Closing — deadline November 9

Hold the cover until October 30, then winterize by November 9, a week ahead of the November 17 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 Flower Mound water runs about 44°F at its winter floor and 86°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 Flower Mound'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.

30°40°50°60°70°80°90°100°JanFebMarAprMayJunJulAugSepOctNovDec65° algae zone58° swimmable startopen Mar 18close Nov 986°F peak44°F floor
Site-model seasonal water estimates for an unheated in-ground pool near Grapevine Dam — ±5°F, see methodology.
JanFebMarAprMayJunJulAugSepOctNovDec
45°47°53°61°68°78°83°86°81°72°60°51°

Warmest water typically June–September (peaking near 86°F); heaters and covers shift any month up.

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

Flower Mound pool season FAQ

When should I open my pool in Flower Mound, TX?

The site model recommends opening by March 18 — about two weeks before Flower Mound'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 Flower Mound opening guide.

When should I close my pool in Flower Mound?

Winterize by November 9. The model holds the deadline a week ahead of Flower Mound's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Flower Mound closing guide.

How long is the swim season in Flower Mound?

Flower Mound averages 157 days a year with normal highs of 80°F or better — about 10 days later than the Texas median. The Texas season index ranks all 68 covered cities by the same metric.

How warm does pool water get in Flower Mound?

An unheated pool near Flower Mound typically peaks around 86°F in high summer and bottoms out near 44°F in winter, spending roughly 3 months at or above the 78°F comfort line most swimmers prefer. 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 Grapevine Dam (6.7 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.