Lake Jacksonville — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Lake Jacksonville, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Lake Jacksonville today is 28.6°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
✅ As of today, the minimum water temperature is above 82°F (28°C). This is very warm water, which may feel almost hot to most people. Swimming in such conditions is perfect for those seeking relaxation and comfort in the water. These waters are often preferred for relaxation in hot weather, as the water temperature does not cool the body significantly. However, it is important to remember that in such warm waters, caution is necessary, as prolonged exposure without rest can lead to overheating. 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 |
|---|---|---|---|
| AUG 4 | 27.6°C | 26.0°C | |
| AUG 5 | 28.0°C | 26.0°C | |
| AUG 6 | 28.2°C | 26.0°C | |
| AUG 7 | 28.2°C | 26.0°C | |
| AUG 8 | 28.3°C | 26.0°C | |
| AUG 9 | 28.6°C | 26.0°C | |
| AUG 10 | 28.6°C | 26.0°C | |
| AUG 11 | 28.8°C | 26.0°C | |
| AUG 12 | 26.0°C | 28.5°C | |
| AUG 13 | 26.0°C | 28.3°C | |
| AUG 14 | 26.0°C | 28.2°C | |
| AUG 15 | 26.0°C | 28.1°C | |
| AUG 16 | 26.0°C | 28.0°C | |
| AUG 17 | 26.0°C | 27.8°C | |
| AUG 18 | 26.0°C | 27.7°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 | 0°C | 2°C | 5°C |
| February | 1°C | 4°C | 6°C |
| March | 3°C | 7°C | 11°C |
| April | 8°C | 13°C | 19°C |
| May | 15°C | 19°C | 24°C |
| June | 19°C | 23°C | 27°C |
| July | 24°C | 28°C | 31°C |
| August | 23°C | 26°C | 29°C |
| September | 22°C | 24°C | 27°C |
| October | 18°C | 21°C | 24°C |
| November | 6°C | 12°C | 18°C |
| December | 1°C | 4°C | 8°C |
Lake Jacksonville: Water Temperature by Location
Lake Jacksonville: Weather Forecast
August 12
August 13
August 14
August 15
August 16
Location & Local Information
Lake Jacksonville is a midwestern reservoir whose surface water temperature follows the seasonal cycle typical of inland Illinois lakes. In winter the lake hovers near freezing, roughly 32–40°F (0–4°C). As air temperatures warm in spring the surface climbs into the mid-40s to mid-60s Fahrenheit (about 7–18°C). Peak summer surface readings commonly reach the low 70s to low 80s °F (approximately 21–28°C), particularly in shallow, sheltered areas on calm days. In autumn the water cools again, often settling into a 50–65°F range (10–18°C) before approaching winter lows. Local weather, wind, and depth create variability from day to day and between shallow and deep sections.
Swimming is generally permitted at Lake Jacksonville in designated areas during the warmer months when beach facilities are open and public health officials have cleared the water. Access and hours are controlled by the managing agency, and swimming may be restricted temporarily for safety reasons such as poor water quality (algal blooms or bacterial contamination), hazardous conditions, or lack of lifeguard coverage. Because temperatures outside summer are often brisk and currents or sudden depth changes can occur, most recreational swimming is concentrated in late spring through summer when surface temperatures are most comfortable and seasonal oversight is in place.