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

Lewis Lake Water Temperature

Lewis Lake in Kanabec County, Minnesota typically sits around 56°F at the surface in September — warmest in Aug (~63°F) and coldest in Sep (~56°F). That is a typical value for the month, not a live reading.

Typical in September
56°F
Cold
Summer average
60°F
Warmest (Aug)
63°F
Coldest (Sep)
56°F

Typical water temperature by month

Jan
Feb
Mar
Apr
May
57°
Jun
59°
Jul
58°
Aug
63°
Sep
56°
Oct
Nov
Dec

Typical surface water temperature by month, from 46 field readings (20102025) via the EPA Water Quality Portal. Months with too few readings are left blank.

Is Lewis Lake warm enough to swim?

At its summer peak (~60°F): Cool

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

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

Where to stay near Lewis Lake

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

Lewis Lake typically sits around 56°F at the surface in September, from 46 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.

When is Lewis Lake warmest?

Surface water at Lewis 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 Lewis Lake warm enough to swim?

At its typical summer peak of about 60°F, Lewis Lake rates as "cool" for swimming. Brisk but swimmable for short dips — most people acclimate after the first few minutes.

Where does this Lewis 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 — 46 readings from 3 monitoring stations between 2010 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.