Milwaukee Harbor Lake Water Temperature
Milwaukee Harbor Lake in Milwaukee County, Wisconsin typically sits around 64°F at the surface in October — warmest in Sep (~70°F) and coldest in Mar (~41°F). That is a typical value for the month, not a live reading.
Typical water temperature by month
Column height runs from this lake’s coldest month (41°F) to its warmest (70°F).
Typical surface water temperature by month, from 244 field readings (2024–2025) via the EPA Water Quality Portal. Months with too few readings are left blank.
Is Milwaukee Harbor Lake warm enough to swim?
Brisk but swimmable for short dips — most people acclimate after the first few minutes.
Want more than temperature? Milwaukee Harbor Lake water quality: clarity, algae, phosphorus, depth, fish species, and current advisories, all on one page.
Water temperatures at nearby Wisconsin lakes
Summer average ~66°F
Summer average ~75°F
Summer average ~78°F
Summer average ~76°F
Summer average ~77°F
Summer average ~76°F
Explore water temperatures
Where to stay near Milwaukee Harbor Lake
Planning a swim or lake trip? Compare cabins, lodges, and vacation rentals near Milwaukee Harbor 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 Milwaukee Harbor Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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Frequently asked questions
What is the water temperature of Milwaukee Harbor Lake?
Milwaukee Harbor Lake typically sits around 64°F at the surface in October, from 244 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
When is Milwaukee Harbor Lake warmest?
Surface water at Milwaukee Harbor Lake is typically warmest in September, reaching about 70°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 Milwaukee Harbor Lake warm enough to swim?
At its typical summer peak of about 63°F, Milwaukee Harbor Lake rates as "cool" for swimming. Brisk but swimmable for short dips — most people acclimate after the first few minutes.
Where does this Milwaukee Harbor 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 — 244 readings from 2 monitoring stations 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.