Headquarters Bay Lake Water Temperature
Headquarters Bay Lake in Cass County, Minnesota averages about 72°F at the surface in summer — warmest in Aug (~73°F) and coldest in Sep (~68°F). These are typical values by month, not a live reading.
Typical water temperature by month
Typical surface water temperature by month, from 37 field readings (2022–2023) via the EPA Water Quality Portal. Months with too few readings are left blank.
Is Headquarters Bay Lake warm enough to swim?
Pleasant for swimming — the range most people find enjoyable without a wetsuit.
Want more than temperature? Headquarters Bay Lake scored B on water quality — clarity, algae, phosphorus, depth, fish species, and swimming safety, all on one report card.
Water temperatures at nearby Minnesota lakes
Summer average ~72°F
Summer average ~73°F
Summer average ~71°F
Summer average ~68°F
Summer average ~62°F
Summer average ~71°F
Explore water temperatures
Where to stay near Headquarters Bay Lake
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Frequently asked questions
What is the water temperature of Headquarters Bay Lake?
Headquarters Bay Lake has a typical summer surface temperature of about 72°F. It is usually warmest in August (around 73°F) and coldest in September (around 68°F). These are typical values by month from 37 EPA Water Quality Portal field readings (2022–2023), not a live reading.
When is Headquarters Bay Lake warmest?
Surface water at Headquarters Bay Lake is typically warmest in August, reaching about 73°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 Headquarters Bay Lake warm enough to swim?
At its typical summer peak of about 72°F, Headquarters Bay Lake rates as "comfortable" for swimming. Pleasant for swimming — the range most people find enjoyable without a wetsuit.
Where does this Headquarters Bay 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 — 37 readings from 1 monitoring station between 2022 and 2023. 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.