Grand River Weather Forecast
- 70
- 86
Chance Thunderstorms
- 65
- 84
Rain Showers Likely
- 60
- 71
Rain Showers Likely
- 55
- 62
Chance Rain Showers
- 51
- 61
Mostly Cloudy
- 57
- 65
Chance Rain Showers
Today 18 Sep Decatur
Mostly cloudy in the Morning, then becoming mostly sunny. Patchy fog in the morning. Humid with Highs in the mid 80s. East Winds 5 to 10 Mph, becoming southeast in the afternoon.
Tonight 18 Sep Decatur
Partly cloudy in the Evening, then mostly cloudy with a chance of Showers and Thunderstorms after midnight. Humid with Lows around 70. South Winds 5 to 10 Mph. Chance of rain 50 percent.
Grand River Temperature Statistics
September Temperature
Lamoni, Lamoni Municipal Airport (13 miles)
Lowest 14 September, 2026
55 °FAverage September
76.5 °FHighest 2 September, 2026
97.6 °F
Climate (2021–2026)
Lamoni, Lamoni Municipal Airport (13 miles)
Average Low 2021–2026
43.6 °FAverage 2021–2026
53.7 °FAverage High 2021–2026
63.9 °F