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

South Twin Lake Water Temperature

South Twin Lake in Itasca County, Minnesota typically sits around 57°F at the surface in September — warmest in Aug (~70°F) and coldest in Jun (~53°F). That is a typical value for the month, not a live reading.

Typical in September
57°F
Cold
Summer average
63°F
Warmest (Aug)
70°F
Coldest (Jun)
53°F

Typical water temperature by month

Jan
Feb
Mar
Apr
May
53°
Jun
67°
Jul
70°
Aug
57°
Sep
Oct
Nov
Dec

Column height runs from this lake’s coldest month (53°F) to its warmest (70°F).

Typical surface water temperature by month, from 39 field readings (2016–2022) via the EPA Water Quality Portal. Months with too few readings are left blank.

Is South Twin Lake warm enough to swim?

At its summer peak (~63°F): Cool

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

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

Where to stay near South Twin Lake

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

South Twin Lake typically sits around 57°F at the surface in September, from 39 EPA Water Quality Portal field readings (2016–2022). That is a typical value for the month, not a live reading.

When is South Twin Lake warmest?

Surface water at South Twin Lake is typically warmest in August, reaching about 70°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 South Twin Lake warm enough to swim?

At its typical summer peak of about 63°F, South Twin Lake rates as "cool" for swimming. Brisk but swimmable for short dips — most people acclimate after the first few minutes.

Where does this South Twin 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 — 39 readings from 1 monitoring station between 2016 and 2022. 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.