Tolna Dam Lake Water Temperature
Tolna Dam Lake in Nelson County, North Dakota averages about 67°F at the surface in summer — warmest in Aug (~71°F) and coldest in Oct (~55°F). These are typical values by month, not a live reading.
Typical water temperature by month
Typical surface water temperature by month, from 12 field readings (2010–2025) via the EPA Water Quality Portal. Months with too few readings are left blank.
Is Tolna Dam Lake warm enough to swim?
Brisk but swimmable for short dips — most people acclimate after the first few minutes.
Want more than temperature? Tolna Dam Lake scored D 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 ~63°F
Summer average ~58°F
Summer average ~61°F
Summer average ~67°F
Summer average ~66°F
Summer average ~66°F
Explore water temperatures
Where to stay near Tolna Dam Lake
Planning a swim or lake trip? Compare cabins, lodges, and vacation rentals near Tolna Dam Lake — live availability and prices.
Top-rated places to stay near Tolna Dam Lake
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a trip to Tolna Dam Lake?
Get lake water-quality report cards plus the best cabin & lodging deals near Tolna Dam Lake — straight to your inbox. No spam, unsubscribe anytime.
Frequently asked questions
What is the water temperature of Tolna Dam Lake?
Tolna Dam Lake has a typical summer surface temperature of about 67°F. It is usually warmest in August (around 71°F) and coldest in October (around 55°F). These are typical values by month from 12 EPA Water Quality Portal field readings (2010–2025), not a live reading.
When is Tolna Dam Lake warmest?
Surface water at Tolna Dam Lake is typically warmest in August, reaching about 71°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 Tolna Dam Lake warm enough to swim?
At its typical summer peak of about 67°F, Tolna Dam Lake rates as "cool" for swimming. Brisk but swimmable for short dips — most people acclimate after the first few minutes.
Where does this Tolna Dam 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 — 12 readings from 1 monitoring station between 2010 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.