Sumner, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Sumner, a city in Bremer County, Iowa.
Tonight
49°F
Chance Rain Showers
A chance of rain showers. Mostly cloudy. Low around 49, with temperatures rising to around 53 overnight. South wind around 10 mph. Chance of precipitation is 30%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Sumner
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 49°F | Chance Rain Showers | 10 mph S | 30% |
| Wednesday | 54°F | Rain Showers Likely | 12 to 18 mph WSW | 65% |
| Wednesday Night | 44°F | Rain Showers Likely | 13 to 17 mph WSW | 64% |
| Thursday | 51°F | Rain Showers | 14 mph NW | 75% |
| Thursday Night | 38°F | Mostly Cloudy | 10 to 14 mph N | 10% |
| Friday | 48°F | Partly Sunny | 3 to 12 mph N | 1% |
| Friday Night | 31°F | Partly Cloudy | 2 mph NW | 0% |
| Saturday | 51°F | Mostly Sunny | 1 to 6 mph WSW | 2% |
| Saturday Night | 35°F | Mostly Clear | 6 mph W | 4% |
| Sunday | 57°F | Sunny | 6 to 9 mph WNW | 9% |
| Sunday Night | 37°F | Mostly Clear | 7 mph SW | 1% |
| Monday | 59°F | Mostly Sunny | 7 to 14 mph SW | 0% |
| Monday Night | 40°F | Mostly Clear | 8 mph WNW | 0% |
| Tuesday | 58°F | Sunny | 8 mph WNW | 1% |
Forecast source: National Weather Service (api.weather.gov) for Sumner (42.849, -92.097). Updated through the day.
Growing snapshot for Sumner
Last spring frost
Apr 29
First fall frost
Oct 9
Growing season
162 days
Hardiness zone
5a
More local growing data for Sumner: nearby ZIP 50674 weather · frost dates · planting calendar · Iowa frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Tripoli, Ia (7.4 mi from Sumner). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.