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

Stump Lake Water Temperature

Stump Lake in Beltrami County, Minnesota typically sits around 70°F at the surface in September — warmest in Jul (~76°F) and coldest in Oct (~61°F). That is a typical value for the month, not a live reading.

Typical in September
70°F
Comfortable
Summer average
75°F
Warmest (Jul)
76°F
Coldest (Oct)
61°F

Typical water temperature by month

Jan
Feb
Mar
Apr
May
65°
Jun
74°
Jul
76°
Aug
76°
Sep
70°
Oct
61°
Nov
Dec

Typical surface water temperature by month, from 37 field readings (20212025) via the EPA Water Quality Portal. Months with too few readings are left blank.

Is Stump Lake warm enough to swim?

At its summer peak (~75°F): Comfortable

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

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

Where to stay near Stump Lake

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

Stump Lake typically sits around 70°F at the surface in September, from 37 EPA Water Quality Portal field readings (2021–2025). That is a typical value for the month, not a live reading.

When is Stump Lake warmest?

Surface water at Stump 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 Stump Lake warm enough to swim?

At its typical summer peak of about 75°F, Stump Lake rates as "comfortable" for swimming. Pleasant for swimming — the range most people find enjoyable without a wetsuit.

Where does this Stump 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 — 37 readings from 2 monitoring stations between 2021 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.