Grand River, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Grand River, a city in Decatur County, Iowa.
Overnight
70°F
Slight Chance Showers And Thunderstorms
A slight chance of showers and thunderstorms after 3am. Mostly cloudy. Low around 70, with temperatures rising to around 72 overnight. South southwest wind around 7 mph. Chance of precipitation is 20%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Grand River
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 70°F | Slight Chance Showers And Thunderstorms | 7 mph SSW | 18% |
| Saturday | 83°F | Chance Showers And Thunderstorms | 9 mph SW | 37% |
| Saturday Night | 64°F | Chance Showers And Thunderstorms then Showers And Thunderstorms Likely | 7 mph N | 66% |
| Sunday | 68°F | Chance Rain Showers then Chance Showers And Thunderstorms | 7 to 10 mph NNE | 44% |
| Sunday Night | 58°F | Chance Showers And Thunderstorms then Showers And Thunderstorms Likely | 10 mph NE | 63% |
| Monday | 61°F | Rain Showers Likely | 12 mph NE | 63% |
| Monday Night | 52°F | Chance Rain Showers | 6 to 9 mph NE | 48% |
| Tuesday | 60°F | Mostly Cloudy | 8 mph NE | 9% |
| Tuesday Night | 46°F | Partly Cloudy | 2 to 7 mph NE | 5% |
| Wednesday | 63°F | Mostly Sunny | 5 mph ENE | 2% |
| Wednesday Night | 51°F | Partly Cloudy | 3 mph E | 7% |
| Thursday | 66°F | Slight Chance Rain Showers | 5 mph ESE | 20% |
| Thursday Night | 56°F | Mostly Cloudy then Slight Chance Rain Showers | 3 mph ESE | 21% |
| Friday | 68°F | Slight Chance Rain Showers then Partly Sunny | 2 to 6 mph E | 21% |
Forecast source: National Weather Service (api.weather.gov) for Grand River (40.819, -93.963). Updated through the day.
Growing snapshot for Grand River
Last spring frost
Apr 23
First fall frost
Oct 17
Growing season
176 days
Hardiness zone
5b
More local growing data for Grand River: nearby ZIP 50108 weather · frost dates · planting calendar · Iowa frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Beaconsfield, Ia (4.5 mi from Grand River). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.