Pool season · Indiana
Hammond Pool Season: the Year on One Bar
Last updated: July 15, 2026 · dates · water temp
One bar, one year, one Hammond pool. The season bar below draws everything the model knows — opening window, prime season, closing window — against today's date, with the working details one click away on the opening and closing pages.
Each dot on the bar is one week of Hammond's typical year, colored by what the model says that week is for: gray weeks are off-season, hollow teal marks the opening window (April 29–May 20), solid teal is swim season, and hollow amber is the closing window ending October 6. The black marker is today — its position against the colors is the entire executive summary.
The Hammond pool calendar
Opening — target May 6
Target May 6; the practical window runs April 29–May 20, and the 7-day mean crosses the 61°F threshold around May 20. Cold-water starts are the cheap ones.
Closing — deadline October 6
Hold the cover until September 26, then winterize by October 6, a week ahead of the October 20 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
This is Hammond'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 25° | 24° | 32° | 44° | 55° | 66° | 73° | 73° | 69° | 59° | 46° | 34° |
The curve peaks near 74°F — comfortable-water months here usually involve a heater or a solar cover.
Email me when Hammond hits the closing window
Data: NOAA 1991–2020 climate normals via Park Forest (12.9 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.