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LakeQuality
A wave breaking on the cobble beach of Lake Superior at Duluth, Minnesota, with a wooded headland beyond

Turtle Lake Water Temperature

Turtle Lake in Beltrami County, Minnesota typically sits around 63°F at the surface in September — warmest in Jul (~76°F) and coldest in May (~58°F). That is a typical value for the month, not a live reading.

Typical in September
63°F
Cool
Summer average
71°F
Warmest (Jul)
76°F
Coldest (May)
58°F

Typical water temperature by month

Jan
Feb
Mar
Apr
58°
May
70°
Jun
76°
Jul
67°
Aug
63°
Sep
Oct
Nov
Dec

Column height runs from this lake’s coldest month (58°F) to its warmest (76°F).

Typical surface water temperature by month, from 64 field readings (2016–2025) via the EPA Water Quality Portal. Months with too few readings are left blank.

Is Turtle Lake warm enough to swim?

At its summer peak (~71°F): Comfortable

Pleasant for swimming — the range most people find enjoyable without a wetsuit.

Want more than temperature? Turtle Lake water quality: clarity, algae, phosphorus, depth, fish species, and current advisories, all on one page.

Where to stay near Turtle Lake

Planning a swim or lake trip? Compare cabins, lodges, and vacation rentals near Turtle 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 Turtle Lake

Prices for Oct 23–25, 4 adults. Change dates on the map below.

Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.

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Frequently asked questions

What is the water temperature of Turtle Lake?

Turtle Lake typically sits around 63°F at the surface in September, from 64 EPA Water Quality Portal field readings (2016–2025). That is a typical value for the month, not a live reading.

When is Turtle Lake warmest?

Surface water at Turtle Lake is typically warmest in July, reaching about 76°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 Turtle Lake warm enough to swim?

At its typical summer peak of about 71°F, Turtle Lake rates as "comfortable" for swimming. Pleasant for swimming — the range most people find enjoyable without a wetsuit.

Where does this Turtle 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 — 64 readings from 2 monitoring stations between 2016 and 2025. 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.