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Illinois River

Illinois River Current Water Temperature and Forecast

On this page, you will find comprehensive information about the water temperature in Illinois River, including current readings, historical data and trends, monthly averages, as well as weather forecasts and upcoming temperature predictions. We find every spot where you can swim and tell you what the water temperature is there today and throughout the year.

Current Water Temperature in Illinois River

76°F

TODAY

75°F

YESTERDAY

73°F

A WEEK AGO

As of today, the minimum water temperature in the Illinois River ranges from 75°F (23°C) to 79°F (26°C). This is a very comfortable temperature for swimming, and many people can enjoy prolonged stays in the water without feeling cold. The water is pleasantly warm, making it ideal for relaxation and water sports. This temperature range is particularly popular among tourists, as it combines comfort and safety for health.

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.

Analysis, Historical Data, and Forecast of Water Temperature

Water Temperature Chart for Illinois River Over the Last 30 Days

Today the water temperature in Illinois River is higher than the same day in previous years. The water temperature range here in July is from 63°F to 75°F. The water temperature is trending upward, and it has increased both over the past 30 days and the past week.

The forecasted water temperature values for Illinois River are presented in the table below.

The actual water temperature values near the shore may differ by a few degrees from the stated values. For the development of the forecast, we use our own mathematical model that takes into account the current water temperature changes, historical data, and key weather trends, including wind strength and direction, and air temperature in each specific region.

Daily Water Temperature Chart

DateCurrentAverageForecast
Jun 3073°F65°F
Jul 172°F68°F
Jul 273°F68°F
Jul 374°F68°F
Jul 474°F68°F
Jul 575°F68°F
Jul 675°F68°F
Jul 776°F68°F
Jul 868°F75°F
Jul 968°F75°F
Jul 1068°F74°F
Jul 1168°F74°F
Jul 1268°F74°F
Jul 1368°F73°F
Jul 1468°F73°F
Jul 1568°F73°F
* Current - Actual water temperature value
** Average - Average water temperature on this day in recent years
*** Forecast - Our water temperature forecast

Water Temperature Ranges in Illinois River by Month

January

MinimumAverageMaximum
37°F40°F48°F

February

MinimumAverageMaximum
37°F42°F48°F

March

MinimumAverageMaximum
37°F44°F52°F

April

MinimumAverageMaximum
41°F50°F61°F

May

MinimumAverageMaximum
46°F56°F70°F

June

MinimumAverageMaximum
57°F65°F73°F

July

MinimumAverageMaximum
63°F68°F75°F

August

MinimumAverageMaximum
63°F71°F73°F

September

MinimumAverageMaximum
52°F64°F66°F

October

MinimumAverageMaximum
46°F56°F61°F

November

MinimumAverageMaximum
37°F47°F61°F

December

MinimumAverageMaximum
37°F40°F46°F

Monthly Water Temperature Histogram for Illinois River

Water Temperature in Cities and Towns on Illinois River

Ottawa
United States (Illinois)
76°F
Morris
United States (Illinois)
75°F
United States (Illinois)
79°F

Illinois River Weather

JULY 8

68°F / 88°F
moderate drizzle

rain: 14% | wind: 7 mph

JULY 9

68°F / 86°F
moderate rain showers

rain: 25% | wind: 10 mph

JULY 10

68°F / 86°F
dense intensity drizzle

rain: 25% | wind: 7 mph

JULY 11

70°F / 86°F
light drizzle

rain: 26% | wind: 10 mph

Water Temperature in Illinois River: General Trends and Swimming Opportunities

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.

Geographical Location of Illinois River

Nearby Rivers

Frequently Asked Questions About Illinois River and its Water Temperatures

What is the current water temperature in Illinois River?

The water temperature today in Illinois River ranges from 75°F (23.8°C) to 79°F (26.1°C).

What is the water temperature in Illinois River during the summer months?

The average water temperature in Illinois River during the summer months is typically between 65°F to 71°F (19°C to 21°C), and it can reach up to 75°F (24°C) at its warmest. However, in some years, the temperature may exceed this range.

What is the water temperature in Illinois River in May?

The average water temperature in Illinois River in May ranges from 46°F to 70°F (8°C to 21°C).

What is the water temperature in Illinois River in September?

The average water temperature in Illinois River in September is typically between 52°F to 66°F (11°C to 19°C).

Where does Illinois River flow?

Illinois River flows through United States (Illinois).

Is it possible to swim in the Illinois River?

Yes, it is possible to swim in the Illinois River. However, safety and water quality may vary, so it's advisable to check local conditions.

What major cities are located on Illinois River?

Cities along the course of Illinois River include Peoria (Illinois).