PoolWindow

Pool season · Texas

Allen Pool Season: the Year on One Bar

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

Allen'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.

Resort pool at dusk in a hot, long-season climateAllen, TX — 156 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 Allen'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 13–April 3), solid teal is swim season, and hollow amber is the closing window ending November 4. The black marker is today — its position against the colors is the entire executive summary.

The Allen pool calendar

March 20open by
November 4close by
15680°F+ days
85°Fwater peak

Opening — target March 20

Open by March 20 — a two-week head start on the April 3 crossing keeps startup chemistry small and beats the local service rush.

Full opening guide

Closing — deadline November 4

The window opens October 29 once water leaves the algae zone; the model deadline is November 4, a week ahead of the November 11 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 Allen water runs about 44°F at its winter floor and 85°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 Allen'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 20close Nov 485°F peak44°F floor
Site-model seasonal water estimates for an unheated in-ground pool near Mckinney Municipal Airport — ±5°F, see methodology.
JanFebMarAprMayJunJulAugSepOctNovDec
45°46°53°61°68°78°83°85°81°72°60°50°

Warmest water typically June–September (peaking near 85°F); heaters and covers shift any month up.

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

Allen pool season FAQ

When should I open my pool in Allen, TX?

The site model recommends opening by March 20 — about two weeks before Allen'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 Allen opening guide.

When should I close my pool in Allen?

Winterize by November 4. The model holds the deadline a week ahead of Allen's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Allen closing guide.

How long is the swim season in Allen?

Allen averages 156 days a year with normal highs of 80°F or better — about 12 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 Allen?

An unheated pool near Allen typically peaks around 85°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 Mckinney Municipal Airport (6.9 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.