Harper, IA Weather & Growing Conditions
Today
85°F
Mostly Sunny then Chance Showers And Thunderstorms
A chance of showers and thunderstorms after 3pm. Mostly sunny, with a high near 85. Southwest wind 5 to 10 mph. Chance of precipitation is 40%.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 85°F | Mostly Sunny then Chance Showers And Thunderstorms | 5 to 10 mph SW | 37% |
| Tonight | 65°F | Showers And Thunderstorms Likely | 5 to 10 mph N | 83% |
| Wednesday | 77°F | Showers And Thunderstorms | 5 to 10 mph NE | 80% |
| Wednesday Night | 59°F | Chance Showers And Thunderstorms | 5 to 10 mph N | 54% |
| Thursday | 81°F | Chance Rain Showers then Mostly Sunny | 5 mph NE | 32% |
| Thursday Night | 60°F | Mostly Clear | 0 to 5 mph E | 3% |
| Friday | 84°F | Sunny | 0 to 5 mph SE | 5% |
| Friday Night | 65°F | Slight Chance Showers And Thunderstorms | 5 mph SE | 16% |
| Saturday | 88°F | Sunny then Slight Chance Rain Showers | 5 to 10 mph S | 15% |
| Saturday Night | 70°F | Slight Chance Rain Showers then Mostly Clear | 10 mph S | 15% |
| Sunday | 89°F | Mostly Sunny | 10 to 15 mph S | 11% |
| Sunday Night | 70°F | Slight Chance Showers And Thunderstorms | 10 mph S | 31% |
| Monday | 89°F | Chance Showers And Thunderstorms then Slight Chance Showers And Thunderstorms | 10 to 15 mph S | 31% |
| Monday Night | 71°F | Slight Chance Showers And Thunderstorms | 10 to 15 mph S | 31% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Harper, IA
Last spring frost
Apr 24
First fall frost
Oct 15
Growing season
172 days
Hardiness zone
5b
Explore more for Harper, IA: full frost dates · planting calendar · Iowa frost dates
Climate data from the nearest NOAA station, Sigourney, Ia (8.9 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.