Pool season · Indiana
Hammond Pool Season: the Year on One Bar
Last updated: July 25, 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.
Hammond, IN — 80 swim days a yearEach 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.
Every station tells its own story: compare this curve with Fort Wayne's pool season and Indianapolis's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Indiana season index.
Hammond pool season FAQ
When should I open my pool in Hammond, IN?
The site model recommends opening by May 6 — about two weeks before Hammond'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 Hammond opening guide.
When should I close my pool in Hammond?
Winterize by October 6. The model holds the deadline a week ahead of Hammond's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Hammond closing guide.
How long is the swim season in Hammond?
Hammond averages 80 days a year with normal highs of 80°F or better — about 5 days later than the Indiana median. The Indiana season index ranks all 13 covered cities by the same metric.
How warm does pool water get in Hammond?
An unheated pool near Hammond typically peaks around 74°F in high summer and bottoms out near 23°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 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.