William Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in William Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in William Lake today is 19.4°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
⚠️ As of today, the minimum water temperature ranges from 65°F (18°C) to 68°F (20°C). This is already quite warm water, which is ideal for most people. Swimming becomes comfortable, and prolonged stays in the water do not cause discomfort. This temperature is perfect for family trips and for those who prefer warmer water. It is also comfortable for water sports such as surfing or swimming. 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 |
|---|---|---|---|
| SEP 14 | 20.2°C | 27.0°C | |
| SEP 15 | 19.8°C | 27.0°C | |
| SEP 16 | 19.9°C | 27.0°C | |
| SEP 17 | 20.4°C | 27.0°C | |
| SEP 18 | 19.7°C | 27.0°C | |
| SEP 19 | 19.8°C | 27.0°C | |
| SEP 20 | 19.5°C | 27.0°C | |
| SEP 21 | 19.4°C | 27.0°C | |
| SEP 22 | 27.0°C | 19.8°C | |
| SEP 23 | 27.0°C | 20.2°C | |
| SEP 24 | 27.0°C | 20.5°C | |
| SEP 25 | 27.0°C | 20.9°C | |
| SEP 26 | 27.0°C | 21.3°C | |
| SEP 27 | 27.0°C | 21.7°C | |
| SEP 28 | 27.0°C | 22.1°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 | 6°C | 12°C | 18°C |
| February | 6°C | 11°C | 17°C |
| March | 11°C | 16°C | 22°C |
| April | 17°C | 20°C | 24°C |
| May | 18°C | 23°C | 28°C |
| June | 17°C | 24°C | 31°C |
| July | 24°C | 29°C | 33°C |
| August | 23°C | 28°C | 33°C |
| September | 23°C | 27°C | 31°C |
| October | 21°C | 27°C | 32°C |
| November | 14°C | 18°C | 21°C |
| December | 11°C | 15°C | 18°C |
William Lake: Water Temperature by Location
William Lake: Weather Forecast
September 22
September 23
September 24
September 25
Location & Local Information
William (Bill) Dannelly Reservoir, also known simply as Dannelly Reservoir or Millers Ferry Lake, is located on the Alabama River in the south-central part of the state. The reservoir experiences warm water temperatures for much of the year due to Alabama’s humid subtropical climate. During winter, surface temperatures typically range from 48 to 55°F (9–13°C), remaining cool but not excessively cold. As spring arrives, the lake warms quickly, reaching 63–72°F (17–22°C) by May. In midsummer, surface waters reach their seasonal peak, averaging 82–86°F (28–30°C) in July and August, creating ideal conditions for swimming and boating. During autumn, temperatures slowly decline to around 68–74°F (20–23°C) before cooling further toward winter.
Swimming is allowed and popular in William (Bill) Dannelly Reservoir, especially during the long, warm season that extends from late May through early October. The reservoir’s calm waters, sheltered coves, and sandy shorelines make it suitable for families and recreational swimmers. Several public parks and campgrounds along the shoreline, including those managed by the U.S. Army Corps of Engineers, provide safe access points and designated areas for swimming. Visitors should be mindful of occasional boat traffic and changing water levels, but overall, the reservoir offers a comfortable and scenic environment for summer swimming and relaxation.