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

Marion Lake Water Temperature

Marion Lake in Dakota County, Minnesota typically sits around 56°F at the surface in October — warmest in Jul (~81°F) and coldest in Feb (~38°F). That is a typical value for the month, not a live reading.

Typical in October
56°F
Cold
Summer average
76°F
Warmest (Jul)
81°F
Coldest (Feb)
38°F

Typical water temperature by month

Jan
38°
Feb
Mar
Apr
58°
May
72°
Jun
81°
Jul
75°
Aug
69°
Sep
56°
Oct
45°
Nov
Dec

Column height runs from this lake’s coldest month (38°F) to its warmest (81°F).

Typical surface water temperature by month, from 169 field readings (2010–2025) via the EPA Water Quality Portal. Months with too few readings are left blank.

Is Marion Lake warm enough to swim?

At its summer peak (~76°F): Comfortable

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

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

Where to stay near Marion Lake

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

Marion Lake typically sits around 56°F at the surface in October, from 169 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.

When is Marion Lake warmest?

Surface water at Marion Lake is typically warmest in July, reaching about 81°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 Marion Lake warm enough to swim?

At its typical summer peak of about 76°F, Marion Lake rates as "comfortable" for swimming. Pleasant for swimming — the range most people find enjoyable without a wetsuit.

Where does this Marion 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 — 169 readings from 2 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.