Stewart Lake Water Temperature
Stewart Lake in Lake County, Minnesota averages about 68°F at the surface in summer — warmest in Jul (~72°F) and coldest in May (~53°F). These are typical values by month, not a live reading.
Typical water temperature by month
Typical surface water temperature by month, from 38 field readings (2019–2024) via the EPA Water Quality Portal. Months with too few readings are left blank.
Is Stewart Lake warm enough to swim?
Brisk but swimmable for short dips — most people acclimate after the first few minutes.
Want more than temperature? Stewart Lake scored A on water quality — clarity, algae, phosphorus, depth, fish species, and swimming safety, all on one report card.
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Frequently asked questions
What is the water temperature of Stewart Lake?
Stewart Lake has a typical summer surface temperature of about 68°F. It is usually warmest in July (around 72°F) and coldest in May (around 53°F). These are typical values by month from 38 EPA Water Quality Portal field readings (2019–2024), not a live reading.
When is Stewart Lake warmest?
Surface water at Stewart Lake is typically warmest in July, reaching about 72°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 Stewart Lake warm enough to swim?
At its typical summer peak of about 68°F, Stewart Lake rates as "cool" for swimming. Brisk but swimmable for short dips — most people acclimate after the first few minutes.
Where does this Stewart 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 — 38 readings from 3 monitoring stations between 2019 and 2024. 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.