Pool season · New Hampshire
Dover Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
Dover'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.
Reading it takes ten seconds: 52 dots, one per week. Solid teal is Dover's swim season; the hollow teal run before it (May 15 to June 5) is when to open; the hollow amber run after is when to close, with September 25 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 May 22
Open by May 22 — a two-week head start on the June 5 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline September 25
Hold the cover until September 15, then winterize by September 25, a week ahead of the October 10 freeze normal. Late and cold beats early and warm.
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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 26° | 24° | 30° | 40° | 51° | 60° | 68° | 70° | 65° | 55° | 44° | 34° |
The curve peaks near 70°F — comfortable-water months here usually involve a heater or a solar cover.
Email me when Dover hits the closing window
Data: NOAA 1991–2020 climate normals via Durham 2 N (2.5 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.