Irwin, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Irwin, a city in Shelby County, Iowa.
Today
77°F
Chance Showers And Thunderstorms then Slight Chance Showers And Thunderstorms
A chance of showers and thunderstorms before 9am, then a slight chance of showers and thunderstorms between 9am and 1pm, then a chance of showers and thunderstorms between 1pm and 2pm, then a slight chance of showers and thunderstorms. Mostly cloudy. High near 77, with temperatures falling to around 74 in the afternoon. Northwest wind 3 to 7 mph. Chance of precipitation is 40%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Irwin
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 77°F | Chance Showers And Thunderstorms then Slight Chance Showers And Thunderstorms | 3 to 7 mph NW | 36% |
| Tonight | 59°F | Chance Showers And Thunderstorms | 8 mph N | 30% |
| Sunday | 64°F | Chance Rain Showers | 8 to 12 mph NE | 39% |
| Sunday Night | 54°F | Chance Rain Showers | 7 to 10 mph NE | 42% |
| Monday | 59°F | Rain Showers Likely | 9 mph ENE | 59% |
| Monday Night | 49°F | Chance Rain Showers then Mostly Cloudy | 3 to 8 mph ENE | 47% |
| Tuesday | 60°F | Partly Sunny | 3 to 7 mph ENE | 5% |
| Tuesday Night | 45°F | Partly Cloudy | 0 to 5 mph E | 1% |
| Wednesday | 64°F | Mostly Sunny | 1 to 5 mph ESE | 1% |
| Wednesday Night | 50°F | Partly Cloudy then Slight Chance Rain Showers | 0 to 3 mph SE | 17% |
| Thursday | 65°F | Slight Chance Rain Showers | 1 to 6 mph SE | 24% |
| Thursday Night | 54°F | Mostly Cloudy then Slight Chance Rain Showers | 3 mph SE | 18% |
| Friday | 67°F | Slight Chance Rain Showers then Mostly Cloudy | 1 to 7 mph SE | 18% |
| Friday Night | 55°F | Mostly Cloudy then Slight Chance Rain Showers | 5 mph SE | 17% |
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 Sep 19, 2026.