Milwaukee River Lake Water Temperature
Milwaukee River Lake in Milwaukee County, Wisconsin averages about 66°F at the surface in summer — warmest in Sep (~72°F) and coldest in Mar (~43°F). These are typical values by month, not a live reading.
Typical water temperature by month
Typical surface water temperature by month, from 246 field readings (2024–2025) via the EPA Water Quality Portal. Months with too few readings are left blank.
Is Milwaukee River Lake warm enough to swim?
Brisk but swimmable for short dips — most people acclimate after the first few minutes.
Want more than temperature? Milwaukee River Lake scored C on water quality — clarity, algae, phosphorus, depth, fish species, and swimming safety, all on one report card.
Water temperatures at nearby Wisconsin lakes
Summer average ~65°F
Summer average ~72°F
Summer average ~62°F
Summer average ~63°F
Summer average ~75°F
Summer average ~78°F
Explore water temperatures
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Frequently asked questions
What is the water temperature of Milwaukee River Lake?
Milwaukee River Lake has a typical summer surface temperature of about 66°F. It is usually warmest in September (around 72°F) and coldest in March (around 43°F). These are typical values by month from 246 EPA Water Quality Portal field readings (2024–2025), not a live reading.
When is Milwaukee River Lake warmest?
Surface water at Milwaukee River Lake is typically warmest in September, reaching about 72°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 River Lake warm enough to swim?
At its typical summer peak of about 66°F, Milwaukee River Lake rates as "cool" for swimming. Brisk but swimmable for short dips — most people acclimate after the first few minutes.
Where does this Milwaukee River 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 — 246 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.