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

Six Mile Lake Water Temperature

Six Mile Lake in Cass County, Minnesota typically sits around 61°F at the surface in September — warmest in Aug (~63°F) and coldest in May (~51°F). That is a typical value for the month, not a live reading.

Typical in September
61°F
Cool
Summer average
61°F
Warmest (Aug)
63°F
Coldest (May)
51°F

Typical water temperature by month

Jan
Feb
Mar
Apr
May
51°
Jun
58°
Jul
61°
Aug
63°
Sep
61°
Oct
57°
Nov
Dec

Typical surface water temperature by month, from 449 field readings (20222025) via the EPA Water Quality Portal. Months with too few readings are left blank.

Is Six Mile Lake warm enough to swim?

At its summer peak (~61°F): Cool

Brisk but swimmable for short dips — most people acclimate after the first few minutes.

Want more than temperature? Six Mile Lake scored A on water quality — clarity, algae, phosphorus, depth, fish species, and swimming safety, all on one report card.

Where to stay near Six Mile Lake

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

Prices for Sep 4–6, 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 Six Mile Lake?

Six Mile Lake typically sits around 61°F at the surface in September, from 449 EPA Water Quality Portal field readings (2022–2025). That is a typical value for the month, not a live reading.

When is Six Mile Lake warmest?

Surface water at Six Mile Lake is typically warmest in August, reaching about 63°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 Six Mile Lake warm enough to swim?

At its typical summer peak of about 61°F, Six Mile Lake rates as "cool" for swimming. Brisk but swimmable for short dips — most people acclimate after the first few minutes.

Where does this Six Mile 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 — 449 readings from 3 monitoring stations between 2022 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.