Winthrop, IA Weather & Growing Conditions
Tonight
65°F
Chance Showers And Thunderstorms
A chance of showers and thunderstorms before 1am, then showers and thunderstorms. Mostly cloudy. Low around 65, with temperatures rising to around 67 overnight. Southeast wind 10 to 15 mph. Chance of precipitation is 80%. New rainfall amounts between three quarters and one inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 65°F | Chance Showers And Thunderstorms | 10 to 15 mph SE | 81% |
| Saturday | 79°F | Showers And Thunderstorms Likely | 10 mph S | 73% |
| Saturday Night | 60°F | Showers And Thunderstorms Likely | 10 to 15 mph N | 59% |
| Sunday | 67°F | Chance Rain Showers | 15 mph NE | 51% |
| Sunday Night | 54°F | Slight Chance Rain Showers | 15 mph NE | 23% |
| Monday | 62°F | Chance Rain Showers | 15 mph NE | 50% |
| Monday Night | 49°F | Chance Rain Showers | 10 to 15 mph NE | 50% |
| Tuesday | 61°F | Chance Rain Showers | 10 to 15 mph NE | 37% |
| Tuesday Night | 46°F | Partly Cloudy | 5 to 10 mph NE | 5% |
| Wednesday | 65°F | Mostly Sunny | 5 mph NE | 1% |
| Wednesday Night | 50°F | Partly Cloudy | 5 mph E | 3% |
| Thursday | 67°F | Mostly Sunny | 5 mph E | 8% |
| Thursday Night | 53°F | Partly Cloudy | 5 mph E | 7% |
| Friday | 68°F | Mostly Sunny | 5 mph NE | 4% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Winthrop, IA
Last spring frost
Apr 30
First fall frost
Oct 7
Growing season
159 days
Hardiness zone
5a
Explore more for Winthrop, IA: full frost dates · planting calendar · Iowa frost dates
Climate data from the nearest NOAA station, Independence #1, Ia (10.8 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.