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

Fish Lake Water Temperature

Fish Lake in Jackson County, Minnesota typically sits around 72°F at the surface in September — warmest in Jul (~77°F) and coldest in Apr (~52°F). That is a typical value for the month, not a live reading.

Typical in September
72°F
Comfortable
Summer average
74°F
Warmest (Jul)
77°F
Coldest (Apr)
52°F

Typical water temperature by month

Jan
Feb
Mar
Apr
52°
May
61°
Jun
70°
Jul
77°
Aug
76°
Sep
72°
Oct
63°
Nov
Dec

Typical surface water temperature by month, from 402 field readings (20222025) via the EPA Water Quality Portal. Months with too few readings are left blank.

Is Fish Lake 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? Fish Lake scored C on water quality — clarity, algae, phosphorus, depth, fish species, and swimming safety, all on one report card.

Where to stay near Fish Lake

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

Fish Lake typically sits around 72°F at the surface in September, from 402 EPA Water Quality Portal field readings (2022–2025). That is a typical value for the month, not a live reading.

When is Fish Lake warmest?

Surface water at Fish Lake is typically warmest in July, reaching about 77°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 Fish Lake warm enough to swim?

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

Where does this Fish 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 — 402 readings from 4 monitoring stations between 2022 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.