Illinois River — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in the Illinois River, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in the Illinois River today is 17.4°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
⚠️ As of today, the minimum water temperature ranges from 60°F (15°C) to 65°F (18°C). The water is comfortable for most people, making it an ideal range for water sports enthusiasts. The temperature does not cause significant discomfort, and swimming will be pleasant for the majority. However, it's important to remember that prolonged exposure to the water can still lead to cooling, so it's essential to monitor the time spent in the water, especially for children or elderly people. 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 | 17.1°C | 15.0°C | |
| OCT 6 | 17.7°C | 15.0°C | |
| OCT 7 | 18.0°C | 15.0°C | |
| OCT 8 | 16.1°C | 15.0°C | |
| OCT 9 | 17.2°C | 15.0°C | |
| OCT 10 | 17.4°C | 15.0°C | |
| OCT 11 | 16.3°C | 15.0°C | |
| OCT 12 | 17.2°C | 15.0°C | |
| OCT 13 | 15.0°C | 17.3°C | |
| OCT 14 | 15.0°C | 17.2°C | |
| OCT 15 | 15.0°C | 17.0°C | |
| OCT 16 | 15.0°C | 16.9°C | |
| OCT 17 | 15.0°C | 16.8°C | |
| OCT 18 | 15.0°C | 16.7°C | |
| OCT 19 | 15.0°C | 16.6°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 | 9°C |
| February | 2°C | 6°C | 9°C |
| March | 3°C | 7°C | 11°C |
| April | 5°C | 11°C | 17°C |
| May | 8°C | 13°C | 21°C |
| June | 14°C | 19°C | 24°C |
| July | 17°C | 22°C | 28°C |
| August | 17°C | 22°C | 27°C |
| September | 11°C | 18°C | 25°C |
| October | 8°C | 15°C | 22°C |
| November | 3°C | 8°C | 16°C |
| December | 2°C | 6°C | 8°C |
Illinois River: Water Temperature by Location
Illinois River: Weather Forecast
October 13
October 14
October 15
October 16
October 17
Location & Local Information
Source Confluence of the Kankakee and Des Plaines Rivers
• location Grundy County, Illinois, United States
Mouth Mississippi River
• location Grafton, Illinois, United States
• elevation 417 ft (127 m)
Length 273 mi (439 km)
The Illinois River, flowing through the heart of Illinois, is a major waterway with diverse recreational opportunities. Its water temperature varies with the seasons, typically ranging from 35°F to 50°F (2°C to 10°C) during the cooler months and warming to 65°F–75°F (18°C–24°C) in the summer. These warmer temperatures in the summer make parts of the river more inviting for water-based activities, though swimming is not the primary focus for most visitors.
Swimming in the Illinois River is possible but is generally limited to specific areas where conditions are safe. Factors like water quality, variable currents, and boat traffic can make swimming less practical in many sections. Designated spots or nearby recreational areas, particularly in tributaries or smaller, calmer sections of the river, are better suited for a refreshing dip. The river is widely enjoyed for boating, fishing, and wildlife observation, providing locals and visitors with numerous ways to experience its beauty and significance in the region.