Green Lake, Wisconsin · Live USGS instrumentation

Big Green Lake ice & water conditions

Name: Big Green Lake ice and water conditions reference
Creator: Sportsman Authority
License: https://creativecommons.org/licenses/by/4.0/

Open-water season. The freeze model activates when the 2026-27 hardwater season begins in November.

Updated Jul 19, 12:16 PM CDT · Species: lake trout, cisco, walleye, panfish

Ring: DNR new-clear-ice reference bands (inches). Model activates when the freeze season begins.

Air temperature · KFLD

78.8 F

Haze · Jul 19, 12:00 PM CDT

Gage height · On-lake gage

6.47 ft

Green Lake at Green Lake · Jul 19, 11:05 AM CDT

30-day trend

Sun

Rise 5:32 AM · Set 8:34 PM

NOAA solar calculation · 43.81, -88.96

Know this lake's data

Wisconsin's deepest natural inland lake (about 237 feet). Deep lakes freeze late and unevenly; early-season ice here lags shallower lakes by weeks.

Ice thickness reference (new, clear ice)

State DNR minimum guidance. It takes at least four days of below-freezing temperatures to form ice that supports a person, and white, layered, or refrozen ice is roughly half as strong: the DNR advises doubling these numbers for it.

Activity	DNR minimum
Stay offNew clear ice below 4 inches does not support a person	Under 4 in
On foot (walking, ice fishing)New, clear ice minimum per Minnesota DNR	4 in or more
Snowmobile or small ATV	5 to 7 in
Side-by-side or full-size ATV	7 to 8 in
Small car or SUVDriving on ice is never recommended	9 to 10 in
Medium SUV or small truck	11 to 12 in
Medium truck	13 in or more

Sources: Minnesota DNR: Ice safety guidelines · Wisconsin DNR: Ice safety

Read this before you go out · draft, pending review (G3)

No ice is ever one hundred percent safe. This page is an educational reference built from public data and state DNR guidance. It is not a measurement of the ice on this lake, and it is not a statement that any ice will hold you.

Ice thickness varies across a single lake and can change overnight. Springs, current, snow load, slush, and refrozen cracks all produce weak ice that no model or nearby sensor can see.

Check the ice yourself, continuously: drill or spud test holes as you go, starting at shore. Carry ice picks, a throw rope, and a flotation aid. Never go out alone, and never drive out early or late season. When in doubt, stay off.

Sportsman Authority provides this reference as-is, without warranty. Decisions on the ice are yours alone.

Data sources

USGS USGS-434840089000001 (Green Lake at Green Lake)US Geological Survey
NWS station KFLD observationsNational Weather Service
Daily temperatures for the freeze model: KFLD via NOAA Regional Climate CentersNOAA Regional Climate Centers
Minnesota DNR: Ice safety guidelinesState agency
Wisconsin DNR: Ice safetyState agency

Data retrieved Jul 19, 2026, 12:16 PM CDT. Readings refresh throughout the day; USGS values may be provisional and subject to revision.

How the model works

Full method, coverage tiers, and every formula on the Ice & Water Report methodology page. Ice guides and gear research live in the ice fishing hub.