Harlan, IA Weather & Growing Conditions
Overnight
40°F
Slight Chance Rain Showers
A slight chance of rain showers before 5am. Cloudy. Low around 40, with temperatures rising to around 43 overnight. Northwest wind around 16 mph, with gusts as high as 24 mph. Chance of precipitation is 20%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 40°F | Slight Chance Rain Showers | 16 mph NW | 21% |
| Wednesday | 49°F | Chance Rain Showers | 16 mph WNW | 35% |
| Wednesday Night | 38°F | Chance Rain Showers | 12 mph WNW | 25% |
| Thursday | 50°F | Chance Rain Showers then Mostly Cloudy | 12 mph NW | 25% |
| Thursday Night | 35°F | Mostly Cloudy | 2 to 8 mph N | 0% |
| Friday | 50°F | Mostly Sunny | 3 mph N | 1% |
| Friday Night | 30°F | Partly Cloudy | 0 mph | 0% |
| Saturday | 53°F | Mostly Sunny | 0 to 5 mph SW | 0% |
| Saturday Night | 34°F | Mostly Clear | 2 mph WSW | 0% |
| Sunday | 59°F | Sunny | 0 to 5 mph WSW | 0% |
| Sunday Night | 37°F | Mostly Clear | 3 mph SSW | 0% |
| Monday | 63°F | Sunny | 3 to 9 mph SW | 0% |
| Monday Night | 39°F | Mostly Clear | 0 to 3 mph WNW | 0% |
| Tuesday | 62°F | Mostly Sunny | 0 to 3 mph NNW | 0% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Harlan, IA
Last spring frost
Apr 27
First fall frost
Oct 9
Growing season
165 days
Hardiness zone
5b
Explore more for Harlan, IA: full frost dates · planting calendar · Iowa frost dates
Climate data from the nearest NOAA station, Harlan, Ia (1.9 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.