Penn Lake Water Temperature
Penn Lake in Hennepin County, Minnesota typically sits around 71°F at the surface in September — warmest in Jul (~83°F) and coldest in Oct (~51°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 42 field readings (2010–2024) via the EPA Water Quality Portal. Months with too few readings are left blank.
Is Penn 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? Penn Lake scored D on water quality — clarity, algae, phosphorus, depth, fish species, and swimming safety, all on one report card.
Water temperatures at nearby Minnesota lakes
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Where to stay near Penn Lake
Planning a swim or lake trip? Compare cabins, lodges, and vacation rentals near Penn Lake — live availability and prices. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Penn Lake
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Frequently asked questions
What is the water temperature of Penn Lake?
Penn Lake typically sits around 71°F at the surface in September, from 42 EPA Water Quality Portal field readings (2010–2024). That is a typical value for the month, not a live reading.
When is Penn Lake warmest?
Surface water at Penn Lake is typically warmest in July, reaching about 83°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 Penn Lake warm enough to swim?
At its typical summer peak of about 80°F, Penn 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 Penn 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 — 42 readings from 1 monitoring station between 2010 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.