Grand River, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Grand River, a city in Decatur County, Iowa.
Today
88°F
Partly Sunny then Slight Chance Showers And Thunderstorms
A slight chance of showers and thunderstorms after 3pm. Partly sunny. High near 88, with temperatures falling to around 86 in the afternoon. South southwest wind around 6 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 |
|---|---|---|---|---|
| Today | 88°F | Partly Sunny then Slight Chance Showers And Thunderstorms | 6 mph SSW | 24% |
| Tonight | 64°F | Showers And Thunderstorms Likely | 9 mph NNE | 69% |
| Wednesday | 75°F | Showers And Thunderstorms Likely | 9 mph NE | 81% |
| Wednesday Night | 60°F | Chance Showers And Thunderstorms | 2 to 9 mph NE | 51% |
| Thursday | 82°F | Slight Chance Showers And Thunderstorms then Mostly Sunny | 5 mph ENE | 17% |
| Thursday Night | 62°F | Mostly Clear | 3 mph ESE | 4% |
| Friday | 87°F | Sunny | 2 to 6 mph S | 6% |
| Friday Night | 67°F | Mostly Clear | 5 mph S | 12% |
| Saturday | 90°F | Sunny | 3 to 10 mph S | 3% |
| Saturday Night | 72°F | Mostly Clear | 13 mph S | 8% |
| Sunday | 92°F | Mostly Sunny | 10 to 14 mph SSW | 8% |
| Sunday Night | 72°F | Partly Cloudy | 13 mph S | 14% |
| Monday | 93°F | Mostly Sunny | 10 to 16 mph SSW | 14% |
| Monday Night | 72°F | Slight Chance Showers And Thunderstorms | 10 to 15 mph SSW | 23% |
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 Aug 4, 2026.