PoolWindow

Pool season · Maryland

Baltimore Pool Season: the Year on One Bar

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

Baltimore'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.

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

off-season opening window swim season closing window

The bar compresses Baltimore's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the April 5–April 26 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends October 24. Wherever the today marker sits, the nearest color change is your next appointment.

The Baltimore pool calendar

April 12open by
October 24close by
11080°F+ days
81°Fwater peak

Opening — target April 12

Target April 12; the practical window runs April 5–April 26, and the 7-day mean crosses the 61°F threshold around April 26. Cold-water starts are the cheap ones.

Full opening guide

Closing — deadline October 24

Hold the cover until October 14, then winterize by October 24, a week ahead of the November 21 freeze normal. Late and cold beats early and warm.

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 Baltimore water runs about 37°F at its winter floor and 81°F at its summer peak.

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

Estimated water temperature by month

Monthly averages of the site's water model run on Baltimore's own normals — the shape of a typical year, not a forecast. The widget above shows where the current year actually sits.

Site-model seasonal water estimates for an unheated in-ground pool near Md Sci Center Baltimore — ±5°F, see methodology.
JanFebMarAprMayJunJulAugSepOctNovDec
38°38°43°53°63°72°80°81°76°66°55°45°

Warmest water typically July–August (peaking near 81°F); heaters and covers shift any month up.

Data: NOAA 1991–2020 climate normals via Md Sci Center Baltimore (1.7 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.