Yellowstone Lake Water Temperature
Yellowstone Lake in Lafayette County, Wisconsin averages about 79°F at the surface in summer — warmest in Aug (~79°F) and coldest in Mar (~46°F). These are typical values by month, not a live reading.
Typical water temperature by month
Typical surface water temperature by month, from 27 field readings (2024–2026) via the EPA Water Quality Portal. Months with too few readings are left blank.
Is Yellowstone Lake warm enough to swim?
Pleasant for swimming — the range most people find enjoyable without a wetsuit.
Want more than temperature? Yellowstone Lake scored F 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 ~78°F
Summer average ~76°F
Summer average ~76°F
Summer average ~67°F
Summer average ~76°F
Summer average ~75°F
Explore water temperatures
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Frequently asked questions
What is the water temperature of Yellowstone Lake?
Yellowstone Lake has a typical summer surface temperature of about 79°F. It is usually warmest in August (around 79°F) and coldest in March (around 46°F). These are typical values by month from 27 EPA Water Quality Portal field readings (2024–2026), not a live reading.
When is Yellowstone Lake warmest?
Surface water at Yellowstone Lake is typically warmest in August, reaching about 79°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 Yellowstone Lake warm enough to swim?
At its typical summer peak of about 79°F, Yellowstone Lake rates as "comfortable" for swimming. Pleasant for swimming — the range most people find enjoyable without a wetsuit.
Where does this Yellowstone 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 — 27 readings from 2 monitoring stations between 2024 and 2026. 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.