Harper, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Harper, a city in Keokuk County, Iowa.
Overnight
68°F
Patchy Fog
Patchy fog and a chance of showers and thunderstorms. Mostly cloudy. Low around 68, with temperatures rising to around 74 overnight. South wind around 5 mph. Chance of precipitation is 50%.
7-day forecast for Harper
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 68°F | Patchy Fog | 5 mph S | 49% |
| Saturday | 82°F | Patchy Fog | 5 to 10 mph S | 78% |
| Saturday Night | 63°F | Chance Showers And Thunderstorms then Showers And Thunderstorms | 5 to 10 mph NW | 84% |
| Sunday | 68°F | Showers And Thunderstorms | 10 to 15 mph NE | 78% |
| Sunday Night | 57°F | Showers And Thunderstorms Likely | 15 mph NE | 60% |
| Monday | 62°F | Rain Showers Likely | 15 mph NE | 60% |
| Monday Night | 51°F | Chance Rain Showers | 10 to 15 mph NE | 45% |
| Tuesday | 60°F | Chance Rain Showers then Partly Sunny | 10 to 15 mph NE | 39% |
| Tuesday Night | 46°F | Partly Cloudy | 5 to 10 mph NE | 4% |
| Wednesday | 64°F | Mostly Sunny | 5 mph NE | 0% |
| Wednesday Night | 51°F | Partly Cloudy | 5 mph NE | 2% |
| Thursday | 66°F | Partly Sunny | 5 mph NE | 7% |
| Thursday Night | 54°F | Partly Cloudy | 5 mph E | 6% |
| Friday | 69°F | Mostly Sunny | 5 mph E | 6% |
Forecast source: National Weather Service (api.weather.gov) for Harper (41.364, -92.051). Updated through the day.
Growing snapshot for Harper
Last spring frost
Apr 24
First fall frost
Oct 15
Growing season
172 days
Hardiness zone
5b
More local growing data for Harper: nearby ZIP 52231 weather · frost dates · planting calendar · Iowa frost dates
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Sigourney
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What Cheer
Climate data from the nearest NOAA station, Sigourney, Ia (8.9 mi from Harper). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.