Raccoon Lake Water Temperature
Raccoon Lake in Marion County, Illinois typically sits around 82°F at the surface in August — warmest in Jul (~85°F) and coldest in Nov (~54°F). That is a typical value for the month, not a live reading.
Typical water temperature by month
Typical surface water temperature by month, from 53 field readings (2011–2021) via the EPA Water Quality Portal. Months with too few readings are left blank.
Is Raccoon Lake warm enough to swim?
Very comfortable for swimming. Warm surface water can also favor blue-green algae in nutrient-rich lakes, so check for advisories before you go in.
Want more than temperature? Raccoon Lake scored F on water quality — clarity, algae, phosphorus, depth, fish species, and swimming safety, all on one report card.
Water temperatures at nearby Illinois lakes
Summer average ~79°F
Summer average ~81°F
Summer average ~77°F
Summer average ~74°F
Summer average ~84°F
Summer average ~80°F
Explore water temperatures
Where to stay near Raccoon Lake
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Frequently asked questions
What is the water temperature of Raccoon Lake?
Raccoon Lake typically sits around 82°F at the surface in August, from 53 EPA Water Quality Portal field readings (2011–2021). That is a typical value for the month, not a live reading.
When is Raccoon Lake warmest?
Surface water at Raccoon Lake is typically warmest in July, reaching about 85°F. Lake surface temperature lags air temperature by several weeks, so the warmest water usually arrives in mid-to-late summer even though the hottest air can come earlier.
Is Raccoon Lake warm enough to swim?
At its typical summer peak of about 81°F, Raccoon Lake rates as "warm" for swimming. Very comfortable for swimming. Warm surface water can also favor blue-green algae in nutrient-rich lakes, so check for advisories before you go in.
Where does this Raccoon Lake water temperature data come from?
Every temperature on this page is a typical (climatological) value computed from real surface-water field readings collected by state and federal agencies and published through the EPA Water Quality Portal — 53 readings from 2 monitoring stations between 2011 and 2021. They describe what is typical for each month, not the temperature right now.
About this data
Water temperatures are a climatology — the typical value for each month, averaged from real surface-water field readings collected by state and federal agencies and published through the EPA Water Quality Portal. They tell you what to expect, not the temperature at this moment. Actual conditions vary with recent weather, depth, and time of day.