Pool season · Pennsylvania
Harrisburg Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
Harrisburg'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 Harrisburg's swim season; the hollow teal run before it (April 25 to May 16) is when to open; the hollow amber run after is when to close, with October 5 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.
The Harrisburg pool calendar
Opening — target May 2
Open by May 2 — a two-week head start on the May 16 crossing keeps startup chemistry small and beats the local service rush.
Closing — deadline October 5
Hold the cover until September 25, then winterize by October 5, a week ahead of the October 23 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
Monthly averages of the site's water model run on Harrisburg'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 31° | 29° | 35° | 45° | 57° | 66° | 74° | 74° | 69° | 59° | 47° | 38° |
The curve peaks near 75°F — comfortable-water months here usually involve a heater or a solar cover.
Email me when Harrisburg hits the closing window
Data: NOAA 1991–2020 climate normals via Harrisburg 1 NE (0.9 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.