Harmony Lake Water Temperature
Harmony Lake in Mercer County, North Dakota typically sits around 61°F at the surface in August — warmest in Jun (~66°F) and coldest in Oct (~49°F). That is a typical value for the month, not a live reading.
Typical water temperature by month
Typical surface water temperature by month, from 18 field readings (2023–2023) via the EPA Water Quality Portal. Months with too few readings are left blank.
Is Harmony Lake warm enough to swim?
Brisk but swimmable for short dips — most people acclimate after the first few minutes.
Want more than temperature? Harmony 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 ~66°F
Summer average ~79°F
Summer average ~64°F
Summer average ~67°F
Summer average ~63°F
Summer average ~60°F
Explore water temperatures
Where to stay near Harmony Lake
Planning a swim or lake trip? Compare cabins, lodges, and vacation rentals near Harmony Lake — live availability and prices. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Harmony Lake
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Frequently asked questions
What is the water temperature of Harmony Lake?
Harmony Lake typically sits around 61°F at the surface in August, from 18 EPA Water Quality Portal field readings (2023–2023). That is a typical value for the month, not a live reading.
When is Harmony Lake warmest?
Surface water at Harmony Lake is typically warmest in June, reaching about 66°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 Harmony Lake warm enough to swim?
At its typical summer peak of about 61°F, Harmony Lake rates as "cool" for swimming. Brisk but swimmable for short dips — most people acclimate after the first few minutes.
Where does this Harmony 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 — 18 readings from 2 monitoring stations between 2023 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.