PoolWindow

Pool season · Idaho

Meridian Pool Season: the Year on One Bar

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

This is the one-page view of Meridian'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 Meridian's swim season; the hollow teal run before it (April 29 to May 20) is when to open; the hollow amber run after is when to close, with October 9 as the deadline; gray is the covered season. Today's marker shows where you stand in that cycle right now.

The Meridian pool calendar

May 6open by
October 9close by
9680°F+ days
79°Fwater peak

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.

Full opening guide

Closing — deadline October 9

Hold the cover until September 29, then winterize by October 9, a week ahead of the October 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 Meridian water runs about 31°F at its winter floor and 79°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 Meridian'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 Boise Air Terminal — ±5°F, see methodology.
JanFebMarAprMayJunJulAugSepOctNovDec
31°34°42°48°56°64°73°78°71°60°46°35°

Warmest water typically August–August (peaking near 79°F); heaters and covers shift any month up.

Data: NOAA 1991–2020 climate normals via Boise Air Terminal (8.5 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.