PoolWindow

Pool season · Michigan

Jackson Pool Season: the Year on One Bar

Last updated: July 15, 2026 · dates · water temp

This is the one-page view of Jackson'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.

J F M A M J J A S O N D today (build date)

off-season opening window swim season closing window

Reading it takes ten seconds: 52 dots, one per week. Solid teal is Jackson's swim season; the hollow teal run before it (May 2 to May 23) is when to open; the hollow amber run after is when to close, with September 30 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.

The Jackson pool calendar

May 9open by
September 30close by
6480°F+ days
72°Fwater peak

Opening — target May 9

Open by May 9 — a two-week head start on the May 23 crossing keeps startup chemistry small and beats the local service rush.

Full opening guide

Closing — deadline September 30

The window opens September 20 once water leaves the algae zone; the model deadline is September 30, a week ahead of the October 14 freeze normal.

Full closing guide

Where the water sits today

SEASONAL VIEW

Estimated unheated pool water temp (site model, ±5°F). The live estimate loads in your browser from Open-Meteo air temperatures; in a typical year Jackson water runs about 24°F at its winter floor and 72°F at its summer peak.

40 45 50 55 60 65 70 75 80 85 58 open 65 algae

Estimated water temperature by month

This is Jackson'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.

Site-model seasonal water estimates for an unheated in-ground pool near Jackson Reynolds Field — ±5°F, see methodology.
JanFebMarAprMayJunJulAugSepOctNovDec
26°25°31°43°54°64°71°71°67°57°45°34°

The curve peaks near 72°F — comfortable-water months here usually involve a heater or a solar cover.

Data: NOAA 1991–2020 climate normals via Jackson Reynolds Field (3.6 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.