Fourth Lake Water Temperature
Fourth Lake in Chisago County, Minnesota averages about 73°F at the surface in summer — warmest in Aug (~75°F) and coldest in Oct (~47°F). These are typical values by month, not a live reading.
Typical water temperature by month
Typical surface water temperature by month, from 76 field readings (2019–2019) via the EPA Water Quality Portal. Months with too few readings are left blank.
Is Fourth Lake warm enough to swim?
Pleasant for swimming — the range most people find enjoyable without a wetsuit.
Want more than temperature? Fourth Lake scored F on water quality — clarity, algae, phosphorus, depth, fish species, and swimming safety, all on one report card.
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Frequently asked questions
What is the water temperature of Fourth Lake?
Fourth Lake has a typical summer surface temperature of about 73°F. It is usually warmest in August (around 75°F) and coldest in October (around 47°F). These are typical values by month from 76 EPA Water Quality Portal field readings (2019–2019), not a live reading.
When is Fourth Lake warmest?
Surface water at Fourth Lake is typically warmest in August, reaching about 75°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 Fourth Lake warm enough to swim?
At its typical summer peak of about 73°F, Fourth Lake rates as "comfortable" for swimming. Pleasant for swimming — the range most people find enjoyable without a wetsuit.
Where does this Fourth 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 — 76 readings from 2 monitoring stations between 2019 and 2019. 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.