Dion Lake Water Temperature
Dion Lake in Rolette County, North Dakota averages about 65°F at the surface in summer — warmest in Jun (~68°F) and coldest in Sep (~51°F). These are typical values by month, not a live reading.
Typical water temperature by month
Typical surface water temperature by month, from 17 field readings (2016–2025) via the EPA Water Quality Portal. Months with too few readings are left blank.
Is Dion Lake warm enough to swim?
Brisk but swimmable for short dips — most people acclimate after the first few minutes.
Want more than temperature? Dion Lake scored C on water quality — clarity, algae, phosphorus, depth, fish species, and swimming safety, all on one report card.
Water temperatures at nearby North Dakota lakes
Summer average ~70°F
Summer average ~65°F
Summer average ~69°F
Summer average ~69°F
Summer average ~66°F
Summer average ~69°F
Explore water temperatures
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Frequently asked questions
What is the water temperature of Dion Lake?
Dion Lake has a typical summer surface temperature of about 65°F. It is usually warmest in June (around 68°F) and coldest in September (around 51°F). These are typical values by month from 17 EPA Water Quality Portal field readings (2016–2025), not a live reading.
When is Dion Lake warmest?
Surface water at Dion Lake is typically warmest in June, reaching about 68°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 Dion Lake warm enough to swim?
At its typical summer peak of about 65°F, Dion Lake rates as "cool" for swimming. Brisk but swimmable for short dips — most people acclimate after the first few minutes.
Where does this Dion 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 — 17 readings from 1 monitoring station between 2016 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.