Pool season · Tennessee
Johnson City Pool Season: the Year on One Bar
Last updated: July 25, 2026 · dates · water temp
This is the one-page view of Johnson City'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.
Johnson City, TN — 108 swim days a yearEach dot on the bar is one week of Johnson City'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 13–May 4), solid teal is swim season, and hollow amber is the closing window ending October 15. The black marker is today — its position against the colors is the entire executive summary.
The Johnson City pool calendar
Opening — target April 20
Target April 20; the practical window runs April 13–May 4, and the 7-day mean crosses the 61°F threshold around May 4. Cold-water starts are the cheap ones.
Closing — deadline October 15
Hold the cover until October 5, then winterize by October 15, a week ahead of the October 24 freeze normal. Late and cold beats early and warm.
Estimated water temperature by month
This is Johnson City'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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 37° | 37° | 43° | 51° | 60° | 68° | 74° | 74° | 71° | 63° | 51° | 42° |
The curve peaks near 75°F — comfortable-water months here usually involve a heater or a solar cover.
Every station tells its own story: compare this curve with Jackson's pool season and Kingsport's — neighboring normals stations can shift the windows by a week or more. The full ranking lives on the Tennessee season index.
Johnson City pool season FAQ
When should I open my pool in Johnson City, TN?
The site model recommends opening by April 20 — about two weeks before Johnson City'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 Johnson City opening guide.
When should I close my pool in Johnson City?
Winterize by October 15. The model holds the deadline a week ahead of Johnson City's NOAA 50% first-freeze date, so the plumbing is protected before the first hard night. The full sequence is in the Johnson City closing guide.
How long is the swim season in Johnson City?
Johnson City averages 108 days a year with normal highs of 80°F or better — about 11 days later than the Tennessee median. The Tennessee season index ranks all 14 covered cities by the same metric.
How warm does pool water get in Johnson City?
An unheated pool near Johnson City typically peaks around 75°F in high summer and bottoms out near 36°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 Johnson City hits the closing window
Data: NOAA 1991–2020 climate normals via Elizabethton (7.4 mi); live outlook by Open-Meteo. Attribution: sources · assumptions: methodology.