Winthrop, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Winthrop, a city in Buchanan County, Iowa.
Overnight
65°F
Chance Showers And Thunderstorms
A chance of showers and thunderstorms before 1am, then showers and thunderstorms likely between 1am and 4am, then patchy fog and occasional showers and thunderstorms. Cloudy, with a low around 65. East wind 10 to 15 mph. Chance of precipitation is 90%. New rainfall amounts between a half and three quarters of an inch possible.
7-day forecast for Winthrop
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 65°F | Chance Showers And Thunderstorms | 10 to 15 mph E | 87% |
| Saturday | 77°F | Patchy Fog | 5 to 10 mph S | 78% |
| Saturday Night | 60°F | Showers And Thunderstorms Likely then Chance Showers And Thunderstorms | 5 to 10 mph N | 68% |
| Sunday | 66°F | Chance Rain Showers | 15 mph NE | 39% |
| Sunday Night | 54°F | Chance Rain Showers | 15 mph NE | 38% |
| Monday | 62°F | Chance Rain Showers | 15 mph NE | 38% |
| Monday Night | 48°F | Chance Rain Showers | 10 to 15 mph NE | 26% |
| Tuesday | 61°F | Chance Rain Showers then Partly Sunny | 10 to 15 mph NE | 25% |
| Tuesday Night | 45°F | Mostly Clear | 5 to 10 mph NE | 4% |
| Wednesday | 65°F | Sunny | 5 to 10 mph NE | 0% |
| Wednesday Night | 49°F | Partly Cloudy | 5 mph NE | 3% |
| Thursday | 66°F | Partly Sunny | 5 mph E | 7% |
| Thursday Night | 52°F | Partly Cloudy | 5 mph E | 5% |
| Friday | 69°F | Mostly Sunny | 5 mph E | 5% |
Forecast source: National Weather Service (api.weather.gov) for Winthrop (42.471, -91.737). Updated through the day.
Growing snapshot for Winthrop
Last spring frost
Apr 30
First fall frost
Oct 7
Growing season
159 days
Hardiness zone
5a
More local growing data for Winthrop: nearby ZIP 50682 weather · frost dates · planting calendar · Iowa frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Independence #1, Ia (10.8 mi from Winthrop). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.