Pool season · Virginia
Arlington Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
This is the one-page view of Arlington'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.
Arlington, VA — 112 swim days a yearReading it takes ten seconds: 52 dots, one per week. Solid teal is Arlington's swim season; the hollow teal run before it (April 3 to April 24) is when to open; the hollow amber run after is when to close, with October 25 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.
The Arlington pool calendar
Opening — target April 10
Open by April 10 — a two-week head start on the April 24 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline October 25
The window opens October 15 once water leaves the algae zone; the model deadline is October 25, a week ahead of the November 18 freeze normal.
Estimated water temperature by month
This is Arlington'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.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 39° | 38° | 44° | 53° | 63° | 72° | 80° | 81° | 76° | 66° | 55° | 45° |
Warmest water typically July–August (peaking near 81°F); heaters and covers shift any month up.
Every station tells its own story: compare this curve with Alexandria's pool season and Charlottesville's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Virginia season index.
Arlington pool season FAQ
When should I open my pool in Arlington, VA?
Open by April 10 — the model places Arlington's 61°F crossing about two weeks later, and every warm day you wait pushes the water toward the 65°F algae zone. The Arlington opening guide has the 12-step sequence.
When should I close my pool in Arlington?
Close by October 25: cool water keeps its winter chemistry, but freeze damage is the hard stop. The Arlington closing guide sequences the work backward from that date.
How long is the swim season in Arlington?
Arlington averages 112 days a year with normal highs of 80°F or better — right on the statewide median. The Virginia season index ranks all 16 covered cities by the same metric.
How warm does pool water get in Arlington?
An unheated pool near Arlington typically peaks around 81°F in high summer and bottoms out near 37°F in winter, spending roughly 2 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 Arlington hits the closing window
Data: NOAA 1991–2020 climate normals via Washington Reagan Airport (4.2 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.