Lake Koshkonong, WI Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Lake Koshkonong, a community in Rock County, Wisconsin.
Today
83°F
Mostly Sunny then Slight Chance Showers And Thunderstorms
A slight chance of showers and thunderstorms after 5pm. Mostly sunny, with a high near 83. Southwest wind around 10 mph. Chance of precipitation is 20%.
7-day forecast for Lake Koshkonong
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 83°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 10 mph SW | 17% |
| Tonight | 64°F | Chance Showers And Thunderstorms then Showers And Thunderstorms | 5 to 10 mph W | 91% |
| Wednesday | 75°F | Patchy Fog then Chance Showers And Thunderstorms | 5 mph NW | 68% |
| Wednesday Night | 59°F | Chance Showers And Thunderstorms | 0 to 5 mph NW | 40% |
| Thursday | 78°F | Slight Chance Rain Showers then Mostly Sunny | 0 mph | 22% |
| Thursday Night | 58°F | Mostly Clear | 0 mph | 7% |
| Friday | 81°F | Mostly Sunny | 0 to 5 mph S | 3% |
| Friday Night | 62°F | Mostly Clear | 5 mph SW | 5% |
| Saturday | 83°F | Sunny then Slight Chance Showers And Thunderstorms | 5 to 10 mph SW | 15% |
| Saturday Night | 67°F | Slight Chance Showers And Thunderstorms | 5 to 10 mph SW | 30% |
| Sunday | 84°F | Chance Showers And Thunderstorms | 10 mph SW | 30% |
| Sunday Night | 66°F | Chance Showers And Thunderstorms | 5 to 10 mph SW | 47% |
| Monday | 83°F | Chance Rain Showers | 5 mph S | 46% |
| Monday Night | 66°F | Chance Showers And Thunderstorms | 5 mph W | 44% |
Forecast source: National Weather Service (api.weather.gov) for Lake Koshkonong (42.861, -88.940). Updated through the day.
Growing snapshot for Lake Koshkonong
Last spring frost
Apr 28
First fall frost
Oct 13
Growing season
166 days
Hardiness zone
5b
More local growing data for Lake Koshkonong: nearby ZIP 53563 weather · frost dates · planting calendar · Wisconsin frost dates
Nearby towns & communities
Brodhead
Clinton
Edgerton
Evansville
Footville
Fulton
Hanover
Janesville
Milton
Orfordville
Shopiere
Climate data from the nearest NOAA station, Ft Atkinson, Wi (9.4 mi from Lake Koshkonong). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.