Portage Lake Water Temperature
Portage Lake in Cook County, Minnesota averages about 57°F at the surface in summer — warmest in Jun (~59°F) and coldest in Sep (~53°F). These are typical values by month, not a live reading.
Typical water temperature by month
Typical surface water temperature by month, from 95 field readings (2018–2019) via the EPA Water Quality Portal. Months with too few readings are left blank.
Is Portage Lake warm enough to swim?
Wetsuit territory. Brief exposure is tolerable but prolonged swimming without protection risks hypothermia.
Want more than temperature? Portage Lake scored B 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 Portage Lake?
Portage Lake has a typical summer surface temperature of about 57°F. It is usually warmest in June (around 59°F) and coldest in September (around 53°F). These are typical values by month from 95 EPA Water Quality Portal field readings (2018–2019), not a live reading.
When is Portage Lake warmest?
Surface water at Portage Lake is typically warmest in June, reaching about 59°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 Portage Lake warm enough to swim?
At its typical summer peak of about 57°F, Portage Lake rates as "cold" for swimming. Wetsuit territory. Brief exposure is tolerable but prolonged swimming without protection risks hypothermia.
Where does this Portage 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 — 95 readings from 1 monitoring station between 2018 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.