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LakeQuality

Side Lake Water Temperature

Side Lake in St. Louis County, Minnesota averages about 61°F at the surface in summer — warmest in Aug (~63°F) and coldest in May (~51°F). These are typical values by month, not a live reading.

Typical in July
61°F
Cool
Summer average
61°F
Warmest (Aug)
63°F
Coldest (May)
51°F

Typical water temperature by month

Jan
Feb
Mar
Apr
May
51°
Jun
59°
Jul
61°
Aug
63°
Sep
61°
Oct
Nov
Dec

Typical surface water temperature by month, from 72 field readings (20182025) via the EPA Water Quality Portal. Months with too few readings are left blank.

Is Side Lake warm enough to swim?

At its summer peak (~61°F): Cool

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

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

Where to stay near Side Lake

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Frequently asked questions

What is the water temperature of Side Lake?

Side Lake has a typical summer surface temperature of about 61°F. It is usually warmest in August (around 63°F) and coldest in May (around 51°F). These are typical values by month from 72 EPA Water Quality Portal field readings (2018–2025), not a live reading.

When is Side Lake warmest?

Surface water at Side Lake is typically warmest in August, reaching about 63°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 Side Lake warm enough to swim?

At its typical summer peak of about 61°F, Side Lake rates as "cool" for swimming. Brisk but swimmable for short dips — most people acclimate after the first few minutes.

Where does this Side 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 — 72 readings from 3 monitoring stations between 2018 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.