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

Island Lake Water Temperature

Island Lake in Aitkin County, Minnesota typically sits around 75°F at the surface in August — warmest in Aug (~75°F) and coldest in May (~61°F). That is a typical value for the month, not a live reading.

Typical in August
75°F
Comfortable
Summer average
73°F
Warmest (Aug)
75°F
Coldest (May)
61°F

Typical water temperature by month

Jan
Feb
Mar
Apr
61°
May
71°
Jun
73°
Jul
75°
Aug
Sep
Oct
Nov
Dec

Column height runs from this lake’s coldest month (61°F) to its warmest (75°F).

Typical surface water temperature by month, from 9 field readings (2025–2025) via the EPA Water Quality Portal. Months with too few readings are left blank.

Is Island Lake warm enough to swim?

At its summer peak (~73°F): Comfortable

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

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

Where to stay near Island Lake

Planning a swim or lake trip? Compare cabins, lodges, and vacation rentals near Island 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 Island 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.

Planning a trip to Island Lake?

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Frequently asked questions

What is the water temperature of Island Lake?

Island Lake typically sits around 75°F at the surface in August, from 9 EPA Water Quality Portal field readings (2025–2025). That is a typical value for the month, not a live reading.

When is Island Lake warmest?

Surface water at Island Lake is typically warmest in August, reaching about 75°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 Island Lake warm enough to swim?

At its typical summer peak of about 73°F, Island Lake rates as "comfortable" for swimming. Pleasant for swimming — the range most people find enjoyable without a wetsuit.

Where does this Island 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 — 9 readings from 1 monitoring station between 2025 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.