Pool season · Texas
Harlingen Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
This is the one-page view of Harlingen'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.
Harlingen, TX — 249 swim days a yearReading it takes ten seconds: 52 dots, one per week. Solid teal is Harlingen's swim season; the hollow teal run before it (January 1 to January 15) is when to open; the hollow amber run after is when to close, with December 27 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.
The Harlingen pool calendar
Opening — target January 1
Target January 1; the practical window runs January 1–January 15, and the 7-day mean crosses the 61°F threshold around January 15. Cold-water starts are the cheap ones.
Closing — deadline December 27
The window opens December 29 once water leaves the algae zone; the model deadline is December 27, a week ahead of the January 3 freeze normal.
Estimated water temperature by month
Monthly averages of the site's water model run on Harlingen's own normals — the shape of a typical year, not a forecast. The widget above shows where the current year actually sits.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 61° | 63° | 68° | 74° | 79° | 84° | 86° | 87° | 86° | 81° | 73° | 66° |
Warmest water typically May–October (peaking near 88°F); heaters and covers shift any month up.
Every station tells its own story: compare this curve with Grand Prairie's pool season and Houston's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Texas season index.
Harlingen pool season FAQ
When should I open my pool in Harlingen, TX?
Open by January 1 — the model places Harlingen's 61°F crossing about two weeks later, and every warm day you wait pushes the water toward the 65°F algae zone. The Harlingen opening guide has the 12-step sequence.
When should I close my pool in Harlingen?
Close by December 27: cool water keeps its winter chemistry, but freeze damage is the hard stop. The Harlingen closing guide sequences the work backward from that date.
How long is the swim season in Harlingen?
Harlingen averages 249 days a year with normal highs of 80°F or better — about 66 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 Harlingen?
An unheated pool near Harlingen typically peaks around 88°F in high summer and bottoms out near 61°F in winter, spending roughly 6 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.
Email me when Harlingen hits the closing window
Data: NOAA 1991–2020 climate normals via Harlingen (1.7 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.