Waterloo, WI Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Waterloo, a city in Jefferson County, Wisconsin.
Today
83°F
Mostly Sunny then Chance Showers And Thunderstorms
A chance of rain showers between 3pm and 4pm, then a chance of showers and thunderstorms. Mostly sunny, with a high near 83. Southwest wind 5 to 10 mph. Chance of precipitation is 30%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Waterloo
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 83°F | Mostly Sunny then Chance Showers And Thunderstorms | 5 to 10 mph SW | 34% |
| Tonight | 62°F | Chance Showers And Thunderstorms then Showers And Thunderstorms | 5 mph W | 87% |
| Wednesday | 75°F | Patchy Fog then Mostly Cloudy | 5 mph W | 51% |
| Wednesday Night | 57°F | Chance Showers And Thunderstorms | 0 to 5 mph W | 25% |
| Thursday | 79°F | Mostly Sunny | 0 mph | 11% |
| Thursday Night | 58°F | Mostly Clear | 0 mph | 7% |
| Friday | 82°F | Sunny | 0 to 5 mph SW | 1% |
| Friday Night | 62°F | Mostly Clear | 5 mph SW | 5% |
| Saturday | 84°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 5 to 10 mph SW | 15% |
| Saturday Night | 67°F | Slight Chance Showers And Thunderstorms | 5 mph S | 31% |
| Sunday | 85°F | Chance Showers And Thunderstorms | 10 mph SW | 31% |
| Sunday Night | 65°F | Slight Chance Showers And Thunderstorms then Chance Showers And Thunderstorms | 5 to 10 mph SW | 49% |
| Monday | 83°F | Chance Rain Showers | 5 mph SW | 47% |
| Monday Night | 65°F | Chance Showers And Thunderstorms | 5 mph N | 42% |
Forecast source: National Weather Service (api.weather.gov) for Waterloo (43.184, -88.990). Updated through the day.
Growing snapshot for Waterloo
Last spring frost
Apr 30
First fall frost
Oct 9
Growing season
163 days
Hardiness zone
5b
More local growing data for Waterloo: nearby ZIP 53594 weather · frost dates · planting calendar · Wisconsin frost dates
Nearby towns & communities
Fort Atkinson
Hebron
Helenville
Ixonia
Jefferson
Johnson Creek
Lake Mills
Palmyra
Rome
Sullivan
Watertown
Climate data from the nearest NOAA station, Waterloo Wwtp, Wi (0.8 mi from Waterloo). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.