PoolWindow

Pool season · Texas

Houston Pool Season: the Year on One Bar

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

This is the one-page view of Houston'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 climateHouston, TX — 186 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

The bar compresses Houston's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the February 11–March 4 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends November 30. Wherever the today marker sits, the nearest color change is your next appointment.

The Houston pool calendar

February 18open by
November 30close by
18680°F+ days
86°Fwater peak

Opening — target February 18

Open by February 18 — a two-week head start on the March 4 crossing keeps startup chemistry small and beats the local service rush.

Full opening guide

Closing — deadline November 30

The window opens November 20 once water leaves the algae zone; the model deadline is November 30, a week ahead of the December 25 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 Houston water runs about 53°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

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

40°50°60°70°80°90°100°JanFebMarAprMayJunJulAugSepOctNovDec65° algae zone58° swimmable startopen Feb 18close Nov 3086°F peak53°F floor
Site-model seasonal water estimates for an unheated in-ground pool near Houston-port — ±5°F, see methodology.
JanFebMarAprMayJunJulAugSepOctNovDec
54°55°61°67°74°81°84°86°84°77°67°59°

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 Harlingen's pool season and Irving's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Texas season index.

Houston pool season FAQ

When should I open my pool in Houston, TX?

Target February 18. That date backs off two weeks from the day Houston's 7-day mean temperature reaches 61°F, so you start up in cold, algae-resistant water. Work the full checklist in the Houston opening guide.

When should I close my pool in Houston?

The closing deadline is November 30 — late enough that the water has cooled out of the algae zone, early enough to beat Houston's first-freeze normal by about a week. See the Houston closing guide for the winterizing steps.

How long is the swim season in Houston?

Houston averages 186 days a year with normal highs of 80°F or better — about 18 days earlier than the Texas median. The Texas season index ranks all 68 covered cities by the same metric.

How warm does pool water get in Houston?

An unheated pool near Houston typically peaks around 86°F in high summer and bottoms out near 53°F in winter, spending roughly 4 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 Houston-port (7.1 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.