Simian Lake Water Temperature
Simian Lake in St. Louis County, Minnesota averages about 66°F at the surface in summer — warmest in Aug (~67°F) and coldest in May (~52°F). These are typical values by month, not a live reading.
Typical water temperature by month
Typical surface water temperature by month, from 126 field readings (2010–2021) via the EPA Water Quality Portal. Months with too few readings are left blank.
Is Simian Lake warm enough to swim?
Brisk but swimmable for short dips — most people acclimate after the first few minutes.
Want more than temperature? Simian Lake scored C 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 Simian Lake?
Simian Lake has a typical summer surface temperature of about 66°F. It is usually warmest in August (around 67°F) and coldest in May (around 52°F). These are typical values by month from 126 EPA Water Quality Portal field readings (2010–2021), not a live reading.
When is Simian Lake warmest?
Surface water at Simian Lake is typically warmest in August, reaching about 67°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 Simian Lake warm enough to swim?
At its typical summer peak of about 66°F, Simian Lake rates as "cool" for swimming. Brisk but swimmable for short dips — most people acclimate after the first few minutes.
Where does this Simian 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 — 126 readings from 1 monitoring station between 2010 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.