Grandfather Lake
Marinette County, Wisconsin · WBIC 500600
This lake has fishing rules that differ from the standard ones for its area. Check the official rules before you fish. Official regulations
Size
14 acres
Max depth
10 ft
DNR lake type
Simple, Harsh
Water clarity
8.4 ft
Moderate, measured Sep 2000
A lake type the DNR marks as having harsh conditions for fish. This describes the lake type in general, not this lake in particular.
Outline
Drawn from the DNR's 24K hydrography (surveyed 1981), so the shape is approximate and a landing can sit a little off the shore. Open the DNR lake map.
Water clarity
8.4 ft Secchi depthModerateOlder reading
Last measured Sep 8, 2000. 2 readings on record, 1999 to 2000.
Only a few readings are on record.
Nothing has been measured in the last 5 years, so this may not match the lake today.
Secchi depth is how far down a white disk stays visible. A bigger number means clearer water. Clear means a Secchi depth of 10 feet or more, moderate 5 to 10 feet, low under 5 feet.
Wisconsin DNR water monitoring (volunteer and staff), via the Water Quality Portal; station GRANDFATHER LAKE - GRANDFATHER LAKE. Checked Oct 23, 2026.
Water temperature
A typical year Modeled estimate
- Ice goes outabout Apr 18 (Apr 6 to Apr 25)
- Surface reaches 48°Fabout Apr 26 (Apr 16 to Apr 29)
- Surface reaches 64°Fabout May 18 (May 9 to May 25)
- June surface71°F, usually 70 to 72°F
- July surface77°F, usually 75 to 78°F
- August surface73°F, usually 71 to 75°F
Forms a warm top layer around Apr 25, lasting about 172 days.
A computer model of this lake's typical weather and water, built from 15 years, 2005 to 2019. Ranges show the middle half of years. The model was not calibrated against measured temperatures for this lake. It is an estimate, not a measurement.
Modeled: U.S. Geological Survey lake temperature data release (doi:10.5066/P9CA6XP8).
Today at the lake
Forecast: National Weather Service (no endorsement implied). Sunrise, sunset and moon phase are calculated. The moon phase can be a day off.
More lakes in Marinette County
- Benson Lake1.4 miles away
- Brock Pond3.3 miles away
- Porcupine Lake3.6 miles away
- Vic Lake4.2 miles away
- Harper Lake5.0 miles away
- Coleman Lake5.8 miles away
Where this comes from
- Size, depth and lake typeWisconsin DNR lake classifications, checked Oct 23, 2026
- OutlineWisconsin DNR 24K hydrography, checked Oct 23, 2026
- Regulations linkWisconsin DNR fishing regulations (linked, not restated), checked Oct 23, 2026
- Water clarityWisconsin DNR water monitoring, via the Water Quality Portal, checked Oct 23, 2026
- Typical-year temperatureU.S. Geological Survey lake temperature model (modeled estimate), checked Oct 23, 2026
- VHS statusWisconsin DNR VHS status by watershed, checked Oct 24, 2026
See data sources for what each source covers, and about for how the numbers are matched to lakes.
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