Winthrop, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Winthrop, a city in Buchanan County, Iowa.
Tonight
60°F
Chance Showers And Thunderstorms
A chance of rain showers before 11pm, then a chance of showers and thunderstorms. Cloudy. Low around 60, with temperatures rising to around 62 overnight. North wind 10 to 15 mph. Chance of precipitation is 50%. New rainfall amounts between a quarter and half of an inch possible.
7-day forecast for Winthrop
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 60°F | Chance Showers And Thunderstorms | 10 to 15 mph N | 53% |
| Sunday | 66°F | Chance Rain Showers | 15 mph NE | 39% |
| Sunday Night | 53°F | Chance Rain Showers | 15 mph NE | 38% |
| Monday | 61°F | Rain Showers Likely | 15 mph NE | 64% |
| Monday Night | 49°F | Rain Showers Likely | 10 to 15 mph NE | 64% |
| Tuesday | 61°F | Chance Rain Showers | 10 to 15 mph NE | 45% |
| Tuesday Night | 46°F | Partly Cloudy | 5 to 10 mph NE | 6% |
| Wednesday | 64°F | Mostly Sunny | 5 to 10 mph NE | 1% |
| Wednesday Night | 50°F | Partly Cloudy | 5 mph E | 2% |
| Thursday | 66°F | Partly Sunny | 5 mph E | 7% |
| Thursday Night | 54°F | Slight Chance Rain Showers | 5 mph E | 18% |
| Friday | 69°F | Slight Chance Rain Showers then Partly Sunny | 5 mph E | 15% |
| Friday Night | 55°F | Partly Cloudy | 5 mph E | 10% |
| Saturday | 70°F | Slight Chance Rain Showers | 5 mph SE | 17% |
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 20, 2026.