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LakeQuality

Lewis Lake Water Temperature

Lewis Lake in Kanabec County, Minnesota averages about 60°F at the surface in summer — warmest in Aug (~63°F) and coldest in Sep (~56°F). These are typical values by month, not a live reading.

Typical in July
58°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 C on water quality — clarity, algae, phosphorus, depth, fish species, and swimming safety, all on one report card.

Where to stay near Lewis Lake

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Frequently asked questions

What is the water temperature of Lewis Lake?

Lewis Lake has a typical summer surface temperature of about 60°F. It is usually warmest in August (around 63°F) and coldest in September (around 56°F). These are typical values by month from 46 EPA Water Quality Portal field readings (2010–2025), 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.