Pool season · Mississippi
Hattiesburg Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
Hattiesburg'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.
Hattiesburg, MS — 170 swim days a yearEach dot on the bar is one week of Hattiesburg's typical year, colored by what the model says that week is for: gray weeks are off-season, hollow teal marks the opening window (March 2–March 23), solid teal is swim season, and hollow amber is the closing window ending November 13. The black marker is today — its position against the colors is the entire executive summary.
The Hattiesburg pool calendar
Opening — target March 9
Target March 9; the practical window runs March 2–March 23, and the 7-day mean crosses the 61°F threshold around March 23. Cold-water starts are the cheap ones.
Closing — deadline November 13
Hold the cover until November 3, then winterize by November 13, a week ahead of the November 23 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
This is Hattiesburg'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 49° | 50° | 56° | 63° | 70° | 77° | 81° | 82° | 80° | 73° | 62° | 54° |
Warmest water typically July–September (peaking near 82°F); heaters and covers shift any month up.
Every station tells its own story: compare this curve with Gulfport's pool season and Jackson's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Mississippi season index.
Hattiesburg pool season FAQ
When should I open my pool in Hattiesburg, MS?
The site model recommends opening by March 9 — about two weeks before Hattiesburg'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 Hattiesburg opening guide.
When should I close my pool in Hattiesburg?
Winterize by November 13. The model holds the deadline a week ahead of Hattiesburg's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Hattiesburg closing guide.
How long is the swim season in Hattiesburg?
Hattiesburg averages 170 days a year with normal highs of 80°F or better — right on the statewide median. The Mississippi season index ranks all 3 covered cities by the same metric.
How warm does pool water get in Hattiesburg?
An unheated pool near Hattiesburg typically peaks around 82°F in high summer and bottoms out near 49°F in winter, spending roughly 3 months at or above the 78°F comfort line most swimmers prefer. The month-by-month curve above shows the whole cycle; the methodology page explains the ±5°F error bars.
Email me when Hattiesburg hits the closing window
Data: NOAA 1991–2020 climate normals via Hattiesburg 5sw (3.9 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.