Williamsport Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Williamsport Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Williamsport Lake today is 21.2°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
✅ As of today, the minimum water temperature ranges from 68°F (20°C) to 74°F (23°C). The water is warm and pleasant for swimming, and in this range, one can stay in the water for extended periods without the risk of hypothermia. This is the ideal temperature for relaxation, swimming, and water sports. Families with children, as well as outdoor enthusiasts, will enjoy swimming and time spent in the water. For most people, this is the optimal temperature for a comfortable beach experience. It is important to note that these swimming tips and recommendations apply only in good weather. When the air temperature is below 68°F (20°C), and sometimes even below 77°F (25°C), swimming can be unpleasant even with relatively high water temperatures.
Water Temperature Chart Over the Last 30 Days
Table of Daily Sea Temperature Data
| Date | Current | Average | Forecast |
|---|---|---|---|
| OCT 5 | 23.6°C | 21.5°C | |
| OCT 6 | 23.6°C | 21.5°C | |
| OCT 7 | 23.4°C | 21.5°C | |
| OCT 8 | 22.6°C | 21.5°C | |
| OCT 9 | 22.8°C | 21.5°C | |
| OCT 10 | 22.1°C | 21.5°C | |
| OCT 11 | 22.6°C | 21.5°C | |
| OCT 12 | 22.1°C | 21.5°C | |
| OCT 13 | 21.5°C | 21.2°C | |
| OCT 14 | 21.5°C | 21.2°C | |
| OCT 15 | 21.5°C | 21.2°C | |
| OCT 16 | 21.5°C | 21.3°C | |
| OCT 17 | 21.5°C | 21.3°C | |
| OCT 18 | 21.5°C | 21.3°C | |
| OCT 19 | 21.5°C | 21.3°C |
* Current - Actual water temperature value
** Average - Average water temperature on this day in recent years
*** Forecast - Our water temperature forecast
Actual nearshore water temperatures may fluctuate by several degrees from the reported values, especially following heavy rainfall or extended periods of strong winds. Certain wind patterns can cause colder, deeper waters to rise and replace the sun-warmed surface water, leading to noticeable variations.
Our forecast is based on a proprietary mathematical model that considers real-time water temperature changes, historical trends, key weather patterns, wind strength and direction, and air temperature specific to each region. Additionally, we incorporate data from other resorts to enhance accuracy.
Monthly Water Temperature Range (Min, Max & Average)
| Month | Min | Avg | Max |
|---|---|---|---|
| January | 5°C | 10°C | 13°C |
| February | 4°C | 9°C | 12°C |
| March | 6°C | 12°C | 18°C |
| April | 12°C | 17°C | 23°C |
| May | 17°C | 21°C | 25°C |
| June | 20°C | 24°C | 27°C |
| July | 22°C | 26°C | 31°C |
| August | 22°C | 26°C | 31°C |
| September | 22°C | 26°C | 30°C |
| October | 17°C | 22°C | 26°C |
| November | 11°C | 14°C | 17°C |
| December | 6°C | 9°C | 13°C |
Williamsport Lake: Water Temperature by Location
Williamsport Lake: Weather Forecast
October 13
October 14
October 15
October 16
October 17
Location & Local Information
Williamsport Lake in Tennessee typically follows the seasonal surface-temperature patterns common to inland Tennessee reservoirs. Winter surface temperatures often fall into the 40–50°F range (about 4–10°C), while spring usually warms into the 50–68°F range (10–20°C). Peak summer temperatures commonly reach roughly 75–86°F (24–30°C) at the surface in shallower areas, and early fall then cools back toward 55–72°F (13–22°C). Actual temperatures will vary by year, depth, time of day and weather; deeper water remains cooler year‑round, and shallow coves warm fastest on sunny days.
Swimming at Williamsport Lake is generally possible when the site is used for recreation, but it depends on local rules and conditions. Many Tennessee lakes allow swimming except where signs, closures or boating zones restrict it; authorities may close water to swimmers for safety reasons such as strong currents, submerged hazards, low visibility, or poor water quality (for example bacterial contamination or harmful algal blooms). Lifeguards are not usually provided at unmanaged lake beaches, so swimmers should heed posted advisories, monitor temperatures—cooler water increases risk of cold shock or hypothermia—and follow local guidance before entering the water.