WisconsinReservoir, 10,602 acres, Jefferson County
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776.18ft
Steady this week
Sailing
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Kayak and SUP
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Power boating
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Fishing
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Outlook. Monday: ENE wind 6 to 11 kt, gusts to 16 kt, high near 60°F. Tuesday: SE wind 7 to 9 kt, gusts to 15 kt, high near 68°F.
7-day wind forecastLoads when you scroll here
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Last hour of NOAA MRMS radar, 1 km resolution. Map data © OpenStreetMap contributors, OpenMapTiles, OpenFreeMap.
776.18ft NAVD88
+0.02 ft in 7 days0.09 ft below the October normal
Reading from Oct 26, 2026. Shaded band: range of October averages on record; dashed line is the typical level.
Lake Koshkonong was at 776.18 ft on October 26, holding steady over the past week (+0.02 ft). That is below normal for October: the typical October level is 776.27 ft, so the lake is 0.09 ft below its usual mark.
Background reading: Lake Koshkonong on Wikipedia
Set in Jefferson County, Wisconsin, Lake Koshkonong is a 10,602-acre reservoir.
We read the level from USGS gauge 05427235, listed as Lake Koshkonong near Newville, WI. Wind and weather come from the National Weather Service grid cell over the lake, so the numbers describe open water rather than the nearest airport.
On a lake this size the wind has miles of open water to work with, so a 15 kt breeze can stack up a steep chop in the main basin while sheltered coves stay flat. Reservoir levels move with releases and inflow, so ramps and beaches can change week to week. The water level page tracks that day by day.
The go or no-go calls above are a starting point, not a guarantee. Read how we score conditions, and always check local rules and posted warnings before you launch.
The National Weather Service forecast for the lake from October 26: Monday: ENE wind 6 to 11 kt, gusts to 16 kt, high near 60°F. The panel at the top of this page refreshes the current wind, gusts and direction when you open it and turns them into a call for sailing, paddling, power boating and fishing.
Lake Koshkonong was at 776.18 ft on October 26, holding steady over the past week (+0.02 ft). That is below normal for October: the typical October level is 776.27 ft, so the lake is 0.09 ft below its usual mark.
Lake Koshkonong covers about 10,602 acres (17 square miles) of surface water.
If Koshkonong is blown out, these are the closest alternatives. Tap through for their conditions.