Juno Lake
Cass County, Michigan241 acresView mapDirections
Nutrients and algae sit mid-range for this region.
- Eutrophic
- Impaired · Mercury
- #7 of 10 in the county
Juno Lake in Cass County, Michigan has a water quality grade of C (Fair). Water clarity: 7.5 ft visibility. Phosphorus: 22 µg/L. Chlorophyll-a (algae): 8.2 µg/L. Surface area: 240.8 acres.
- Clarity
- 7.5 ft
- Typical in September
- 67°F
- Area
- 241 acres
- Type
- Eutrophic
- Trend
- → Stable
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Juno Lake is a 241-acre productive, nutrient-rich eutrophic lake in Cass County, Michigan. Water quality is graded C based on 2 sampling years through 2023. Water clarity is improving over recent sampling years. Compared to the 9 other monitored lakes in Cass County, Juno Lake ranks #7 for water quality.
Source: EPA Water Quality Portal sampling records, EGLE, last sampled 2023-09-20. Grade methodology: LakeQuality methodology.
Swimming Safety
Grade onlyModerate
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The C is nutrients and algae, not a swimming clearance. Juno Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Water Quality Grade: C (Fair)
Moderate clarity, visible to about 7.5 ft. Phosphorus 22 µg/L. Chlorophyll-a 8.2 µg/L. TSI 49. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7.5 ft | Not graded |
| Phosphorus | 22 µg/L | Good |
| Chlorophyll-a (Algae) | 8.2 µg/L | Fair |
| Trophic State Index (TSI) | 49 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Water Temperature
Juno Lake typically sits around 67°F at the surface in September. Summer average is about 66°F. Usually warmest in Aug (about 69°F) and coldest in May (about 58°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 485 field readings (2012–2022) via the EPA Water Quality Portal. See the full Juno Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 241 acres |
No bathymetric survey has been published for Juno Lake, so its depth is not documented here.
Fishing Juno Lake
Water Quality Trend: → Stable
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.275 m/yr | 6 |
| Phosphorus | → Stable | +0.29 µg/L/yr | 5 |
| Chlorophyll-a | ↓ Declining | +0.9 µg/L/yr | 4 |
EPA Impairment Status
Juno Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MI040500011403-03 · Official waterbody report · Matched by proximity (0.27 km)
County Ranking
Ranked #7 of 10 lakes in Cass County
Nearby Lakes With Higher Grades
Juno Lake holds Grade C. 2 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Cass County
Frequently asked questions about Juno Lake
Where is Juno Lake?
- Juno Lake is a lake in Cass County, Michigan. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Juno Lake?
- Juno Lake in Cass County, Michigan has a water quality grade of C (Fair). Water clarity: 7.5 ft visibility. Phosphorus: 22 µg/L. Chlorophyll-a (algae): 8.2 µg/L. Surface area: 240.8 acres.
Is Juno Lake safe to swim in?
- The C is nutrients and algae, not a swimming clearance. Juno Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
What is the water temperature of Juno Lake?
- Juno Lake typically sits around 67°F at the surface in September, from 485 EPA Water Quality Portal field readings (2012–2022). That is a typical value for the month, not a live reading.
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Where this data comes from
99 measurements from 1 monitoring station, 2016–2023. Retrieved from the EPA Water Quality Portal on 2026-08-26.
Collected and reported by
- Michigan EGLE - MiCorps
21MICH_MICORPS99 samples · 2016–2023
Analytical methods
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database