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

Granite Lake at Water Temperature

Granite Lake at in Barron County, Wisconsin typically sits around 70°F at the surface in September — warmest in Jul (~78°F) and coldest in May (~60°F). That is a typical value for the month, not a live reading.

Typical in September
70°F
Comfortable
Summer average
74°F
Warmest (Jul)
78°F
Coldest (May)
60°F

Typical water temperature by month

Jan
Feb
Mar
Apr
60°
May
73°
Jun
78°
Jul
71°
Aug
70°
Sep
Oct
Nov
Dec

Column height runs from this lake’s coldest month (60°F) to its warmest (78°F).

Typical surface water temperature by month, from 16 field readings (2024–2025) via the EPA Water Quality Portal. Months with too few readings are left blank.

Is Granite Lake at warm enough to swim?

At its summer peak (~74°F): Comfortable

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

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

Where to stay near Granite Lake at

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

Prices for Oct 16–18, 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 Granite Lake at?

Granite Lake at typically sits around 70°F at the surface in September, from 16 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.

When is Granite Lake at warmest?

Surface water at Granite Lake at is typically warmest in July, reaching about 78°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 Granite Lake at warm enough to swim?

At its typical summer peak of about 74°F, Granite Lake at rates as "comfortable" for swimming. Pleasant for swimming — the range most people find enjoyable without a wetsuit.

Where does this Granite Lake at 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 — 16 readings from 1 monitoring station between 2024 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.