Pool season · Delaware
Dover Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
This is the one-page view of Dover'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.
Dover, DE — 99 swim days a yearReading it takes ten seconds: 52 dots, one per week. Solid teal is Dover's swim season; the hollow teal run before it (April 12 to May 3) is when to open; the hollow amber run after is when to close, with October 21 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.
The Dover pool calendar
Opening — target April 19
Target April 19; the practical window runs April 12–May 3, and the 7-day mean crosses the 61°F threshold around May 3. Cold-water starts are the cheap ones.
Closing — deadline October 21
The window opens October 11 once water leaves the algae zone; the model deadline is October 21, a week ahead of the November 4 freeze normal.
Estimated water temperature by month
Monthly averages of the site's water model run on Dover'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 37° | 37° | 42° | 51° | 61° | 69° | 77° | 77° | 74° | 65° | 53° | 44° |
The curve peaks near 78°F — comfortable-water months here usually involve a heater or a solar cover.
Dover pool season FAQ
When should I open my pool in Dover, DE?
The site model recommends opening by April 19 — about two weeks before Dover'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 Dover opening guide.
When should I close my pool in Dover?
Winterize by October 21. The model holds the deadline a week ahead of Dover's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Dover closing guide.
How long is the swim season in Dover?
Dover averages 99 days a year with normal highs of 80°F or better — right on the statewide median. The Delaware season index ranks all 1 covered cities by the same metric.
How warm does pool water get in Dover?
An unheated pool near Dover typically peaks around 78°F in high summer and bottoms out near 36°F in winter, never quite reaching the 78°F comfort line without a heater or solar cover. The month-by-month curve above shows the whole cycle; the methodology page explains the ±5°F error bars.
Email me when Dover hits the closing window
Data: NOAA 1991–2020 climate normals via Dover (1.2 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.