← Lake Guide42.87° N · 88.96° W

Wisconsin

Lake Koshkonong

Lake Koshkonong is a Wisconsin lake of about 10,602 acres in Jefferson County, with largemouth fishing keyed to cover, current, and conditions.

Surface
10,602acres
Primary species
Largemouth
§ 01Today on the water · Lake Koshkonongvia Open-Meteo · 14:15 local
Air temp
80.1°F
Barometric
29.81″
↓falling 24h(-0.20)
Wind
13mph
from WNW
Moon
Waxing Crescent
day 4.0 · 17% lit

Air conditions sampled near the lake center, not measured on the water · refreshed ~15 min

§ 03Next 3 daysvia Open-Meteo · interpretation
  1. 18
    julSat

    Stable window

    hi 89° · lo 71°

    Anytime through the day. Quiet weather day; lean on seasonal pattern and structure.

    ── light nw wind

  2. 19
    julSun

    Watch the wind

    hi 85° · lo 65°

    Lean into wind-fed shorelines, all day. Wind drives bait position today; pick the shoreline taking it.

    ── direction shift overnight

  3. 20
    julMon

    Watch the wind

    hi 82° · lo 64°

    Lean into wind-fed shorelines, all day. Wind drives bait position today; pick the shoreline taking it.

    ── direction shift overnight

§ 04Field notesWisconsin

Where it is

Lake Koshkonong sits in Jefferson County, Wisconsin, covering about 10,602 acres. Where the largemouth sit changes with the season, not the map.

Seasonal pattern

Spring. Warming water pulls largemouth toward shallow, protected areas where they stage and spawn; the quickest-warming pockets lead.

Summer. Heat pushes fish off the shallows toward depth and shade; work the cooler ends of the day.

Fall. As water cools, forage and bass return toward shallower water; movement is wide, so covering water pays.

Winter. Cold water settles fish deep and slow; patience and a subtle presentation are the more dependable choice.

Key structure

  • Creek and cove mouths that funnel fish and bait
  • Weed edges and the clean lines along them
  • Inside turns where a bank changes angle
  • Submerged wood, brush, and laydown cover

The calendar decides which of these is worth time on a given day.

Forage

The bait on Lake Koshkonong runs to small panfish and shad-class baitfish; bass set up where those schools move.

Access

Public launches surround Lake Koshkonong; check seasonal closures, water levels, and weather before a trip.

Regulations

Check current state and local regulations before fishing; limits and seasons can change.

§ 05Sources & field guides

Field guides

Data & references

  • Today's conditions — Open-Meteo, refreshed every ~15 min
  • Moon phase — local astronomical calculation, no external API
  • Lake area, depth, structure — Identity, surface area, coordinates and county/state are from the ProjectD canonical waterbody index (snapshot conus-20260518-v1, group gnis:01567632). Maximum depth and regulation links were not available from an acceptable source and are intentionally omitted.
  • Regulations — verify current state and local regulations before fishing

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