Hill Slough Lake Water Temperature
Hill Slough Lake in Sauk County, Wisconsin averages about 67°F at the surface in summer — warmest in Jun (~77°F) and coldest in Oct (~49°F). These are typical values by month, not a live reading.
Typical water temperature by month
Typical surface water temperature by month, from 19 field readings (2025–2025) via the EPA Water Quality Portal. Months with too few readings are left blank.
Is Hill Slough Lake warm enough to swim?
Brisk but swimmable for short dips — most people acclimate after the first few minutes.
Want more than temperature? Hill Slough 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 ~76°F
Summer average ~76°F
Summer average ~75°F
Summer average ~78°F
Summer average ~76°F
Summer average ~76°F
Explore water temperatures
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Frequently asked questions
What is the water temperature of Hill Slough Lake?
Hill Slough Lake has a typical summer surface temperature of about 67°F. It is usually warmest in June (around 77°F) and coldest in October (around 49°F). These are typical values by month from 19 EPA Water Quality Portal field readings (2025–2025), not a live reading.
When is Hill Slough Lake warmest?
Surface water at Hill Slough Lake is typically warmest in June, 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 Hill Slough Lake warm enough to swim?
At its typical summer peak of about 67°F, Hill Slough Lake rates as "cool" for swimming. Brisk but swimmable for short dips — most people acclimate after the first few minutes.
Where does this Hill Slough 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 — 19 readings from 2 monitoring stations between 2025 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.