Jackson Park Outer Harbor Lake Water Temperature
Jackson Park Outer Harbor Lake in Cook County, Illinois averages about 69°F at the surface in summer — warmest in Jul (~77°F) and coldest in Oct (~58°F). These are typical values by month, not a live reading.
Typical water temperature by month
Typical surface water temperature by month, from 10 field readings (2015–2023) via the EPA Water Quality Portal. Months with too few readings are left blank.
Is Jackson Park Outer Harbor Lake warm enough to swim?
Brisk but swimmable for short dips — most people acclimate after the first few minutes.
A live gauge on Jackson Park Outer Harbor Lake last read 65°F. See the full Jackson Park Outer Harbor Lake report card for current conditions and the A–F water-quality grade.
Want more than temperature? Jackson Park Outer Harbor Lake scored D on water quality — clarity, algae, phosphorus, depth, fish species, and swimming safety, all on one report card.
Water temperatures at nearby Illinois lakes
Summer average ~78°F
Summer average ~78°F
Summer average ~76°F
Summer average ~74°F
Summer average ~78°F
Summer average ~75°F
Explore water temperatures
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Frequently asked questions
What is the water temperature of Jackson Park Outer Harbor Lake?
Jackson Park Outer Harbor Lake has a typical summer surface temperature of about 69°F. It is usually warmest in July (around 77°F) and coldest in October (around 58°F). These are typical values by month from 10 EPA Water Quality Portal field readings (2015–2023), not a live reading.
When is Jackson Park Outer Harbor Lake warmest?
Surface water at Jackson Park Outer Harbor Lake is typically warmest in July, reaching about 77°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 Jackson Park Outer Harbor Lake warm enough to swim?
At its typical summer peak of about 69°F, Jackson Park Outer Harbor Lake rates as "cool" for swimming. Brisk but swimmable for short dips — most people acclimate after the first few minutes.
Where does this Jackson Park Outer Harbor 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 — 10 readings from 3 monitoring stations between 2015 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.