Forbes Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Forbes Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Forbes Lake today is 28.5°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 | 27.3°C | 26.7°C | |
| AUG 5 | 27.4°C | 26.7°C | |
| AUG 6 | 28.2°C | 26.7°C | |
| AUG 7 | 28.2°C | 26.7°C | |
| AUG 8 | 28.2°C | 26.7°C | |
| AUG 9 | 28.5°C | 26.7°C | |
| AUG 10 | 28.5°C | 26.7°C | |
| AUG 11 | 28.6°C | 26.7°C | |
| AUG 12 | 26.7°C | 28.4°C | |
| AUG 13 | 26.7°C | 28.3°C | |
| AUG 14 | 26.7°C | 28.2°C | |
| AUG 15 | 26.7°C | 28.1°C | |
| AUG 16 | 26.7°C | 28.1°C | |
| AUG 17 | 26.7°C | 28.0°C | |
| AUG 18 | 26.7°C | 27.9°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 | 1°C | 6°C | 10°C |
| February | 0°C | 4°C | 6°C |
| March | 3°C | 9°C | 15°C |
| April | 9°C | 14°C | 20°C |
| May | 16°C | 20°C | 24°C |
| June | 19°C | 25°C | 30°C |
| July | 24°C | 27°C | 30°C |
| August | 24°C | 27°C | 29°C |
| September | 23°C | 27°C | 31°C |
| October | 14°C | 19°C | 24°C |
| November | 7°C | 11°C | 15°C |
| December | 2°C | 6°C | 9°C |
Forbes Lake: Water Temperature by Location
Forbes Lake: Weather Forecast
August 12
August 13
August 14
August 15
August 16
Location & Local Information
Forbes Lake, like many small inland lakes in Illinois, shows pronounced seasonal swings in surface water temperature. In winter the lake can approach freezing with surface temperatures around 32°F (0°C) and sometimes slightly below the lake’s freezing point where ice forms. During spring it commonly warms from roughly 35–60°F (2–16°C) as air temperatures rise and stratification begins. Peak summer surface temperatures often range from about 70–85°F (21–29°C), with the warmest, most comfortable swimming conditions usually occurring in July and August. By autumn the water cools back down through roughly 60–45°F (16–7°C) before returning to near-freezing in winter. These ranges are approximate and can vary with weather, depth, and local inflows.
Whether swimming is allowed at Forbes Lake depends on local management, posted rules, and current water quality. Some small lakes permit swimming from designated beaches or with lifeguard supervision when bacteria and algae test results are acceptable; others restrict or prohibit swimming because of safety hazards (cold deep water, sudden drop-offs, submerged debris), private ownership, or concerns about harmful algal blooms and bacterial contamination. Anyone considering swimming should follow on-site signage and recent water-quality advisories, since permission and safety conditions can change seasonally.