Irwin, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Irwin, a city in Shelby County, Iowa.
This Afternoon
58°F
Rain Showers Likely
Rain showers likely. Cloudy. High near 58, with temperatures falling to around 53 in the afternoon. North northwest wind around 16 mph, with gusts as high as 25 mph. Chance of precipitation is 70%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Irwin
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 58°F | Rain Showers Likely | 16 mph NNW | 72% |
| Tonight | 40°F | Rain Showers | 13 to 16 mph NW | 87% |
| Wednesday | 50°F | Chance Rain Showers | 13 to 16 mph WNW | 40% |
| Wednesday Night | 38°F | Cloudy then Chance Rain Showers | 8 to 12 mph WNW | 40% |
| Thursday | 51°F | Rain Showers Likely | 12 mph NW | 56% |
| Thursday Night | 35°F | Mostly Cloudy | 3 to 8 mph N | 5% |
| Friday | 51°F | Partly Sunny | 3 mph N | 2% |
| Friday Night | 32°F | Partly Cloudy | 0 mph | 0% |
| Saturday | 57°F | Mostly Sunny | 0 to 5 mph WSW | 2% |
| Saturday Night | 35°F | Mostly Clear | 2 mph W | 4% |
| Sunday | 62°F | Sunny | 1 to 6 mph WSW | 5% |
| Sunday Night | 38°F | Mostly Clear | 5 mph SSW | 0% |
| Monday | 64°F | Sunny | 5 to 10 mph WSW | 0% |
| Monday Night | 40°F | Mostly Clear | 1 to 5 mph NW | 0% |
Forecast source: National Weather Service (api.weather.gov) for Irwin (41.790, -95.207). Updated through the day.
Growing snapshot for Irwin
Last spring frost
Apr 27
First fall frost
Oct 9
Growing season
165 days
Hardiness zone
5a
More local growing data for Irwin: nearby ZIP 51446 weather · frost dates · planting calendar · Iowa frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Harlan, Ia (11.6 mi from Irwin). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.