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

Rush Island Lake Water Temperature

Rush Island Lake in Itasca County, Minnesota typically sits around 68°F at the surface in August — warmest in Aug (~68°F) and coldest in May (~56°F). That is a typical value for the month, not a live reading.

Typical in August
68°F
Cool
Summer average
64°F
Warmest (Aug)
68°F
Coldest (May)
56°F

Typical water temperature by month

Jan
Feb
Mar
Apr
May
56°
Jun
59°
Jul
Aug
68°
Sep
Oct
Nov
Dec

Typical surface water temperature by month, from 38 field readings (20102021) via the EPA Water Quality Portal. Months with too few readings are left blank.

Is Rush Island Lake warm enough to swim?

At its summer peak (~64°F): Cool

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

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

Where to stay near Rush Island Lake

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

Rush Island Lake typically sits around 68°F at the surface in August, from 38 EPA Water Quality Portal field readings (2010–2021). That is a typical value for the month, not a live reading.

When is Rush Island Lake warmest?

Surface water at Rush Island Lake is typically warmest in August, reaching about 68°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 Rush Island Lake warm enough to swim?

At its typical summer peak of about 64°F, Rush Island Lake rates as "cool" for swimming. Brisk but swimmable for short dips — most people acclimate after the first few minutes.

Where does this Rush 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 — 38 readings from 2 monitoring stations between 2010 and 2021. 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.