PoolWindow

Pool season · Florida

St. Augustine Pool Season: the Year on One Bar

Last updated: July 25, 2026 · dates · water temp

This is the one-page view of St. Augustine'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.

Resort pool at dusk in a hot, long-season climateSt. Augustine, FL — 191 swim days a year
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 St. Augustine's whole pool year into one lane rope: gray floats for the off-season, hollow teal for the February 2–February 23 opening window, solid teal for swim weeks, hollow amber for the closing stretch that ends December 20. Wherever the today marker sits, the nearest color change is your next appointment.

The St. Augustine pool calendar

February 9open by
December 20close by
19180°F+ days
83°Fwater peak

Opening — target February 9

Open by February 9 — a two-week head start on the February 23 crossing keeps startup chemistry small and beats the local service rush.

Full opening guide

Closing — deadline December 20

Hold the cover until December 10, then winterize by December 20, a week ahead of the January 5 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 St. Augustine water runs about 58°F at its winter floor and 83°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 St. Augustine'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.

50°60°70°80°90°JanFebMarAprMayJunJulAugSepOctNovDec65° algae zone58° swimmable startopen Feb 9close Dec 2083°F peak58°F floor
Site-model seasonal water estimates for an unheated in-ground pool near St Augustine Lighthouse — ±5°F, see methodology.
JanFebMarAprMayJunJulAugSepOctNovDec
58°59°62°68°74°79°82°82°81°78°70°63°

Warmest water typically June–October (peaking near 83°F); heaters and covers shift any month up.

Every station tells its own story: compare this curve with Spring Hill's pool season and St. Cloud's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Florida season index.

St. Augustine pool season FAQ

When should I open my pool in St. Augustine, FL?

The site model recommends opening by February 9 — about two weeks before St. Augustine'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 St. Augustine opening guide.

When should I close my pool in St. Augustine?

Winterize by December 20. The model holds the deadline a week ahead of St. Augustine's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the St. Augustine closing guide.

How long is the swim season in St. Augustine?

St. Augustine averages 191 days a year with normal highs of 80°F or better — about 16 days later than the Florida median. The Florida season index ranks all 64 covered cities by the same metric.

How warm does pool water get in St. Augustine?

An unheated pool near St. Augustine typically peaks around 83°F in high summer and bottoms out near 58°F in winter, spending roughly 4 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.

Data: NOAA 1991–2020 climate normals via St Augustine Lighthouse (1.6 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.