Winthrop, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Winthrop, a city in Buchanan County, Iowa.
Today
77°F
Chance Showers And Thunderstorms
A chance of showers and thunderstorms after 10am. Partly sunny, with a high near 77. West wind 5 to 10 mph. Chance of precipitation is 50%.
7-day forecast for Winthrop
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 77°F | Chance Showers And Thunderstorms | 5 to 10 mph W | 50% |
| Tonight | 62°F | Showers And Thunderstorms Likely | 5 to 10 mph N | 74% |
| Wednesday | 73°F | Chance Showers And Thunderstorms | 5 mph N | 48% |
| Wednesday Night | 55°F | Slight Chance Rain Showers | 5 mph N | 23% |
| Thursday | 78°F | Sunny | 0 to 5 mph E | 7% |
| Thursday Night | 59°F | Mostly Clear | 0 to 5 mph SE | 1% |
| Friday | 81°F | Sunny | 0 to 10 mph S | 3% |
| Friday Night | 64°F | Mostly Clear | 5 mph S | 10% |
| Saturday | 84°F | Mostly Sunny | 5 to 10 mph S | 11% |
| Saturday Night | 69°F | Slight Chance Rain Showers then Slight Chance Showers And Thunderstorms | 10 to 15 mph S | 20% |
| Sunday | 85°F | Slight Chance Showers And Thunderstorms | 10 mph S | 20% |
| Sunday Night | 69°F | Chance Showers And Thunderstorms | 10 mph S | 41% |
| Monday | 84°F | Chance Showers And Thunderstorms | 10 mph S | 41% |
| Monday Night | 69°F | Slight Chance Showers And Thunderstorms | 10 mph E | 38% |
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 Aug 4, 2026.