Sumner, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Sumner, a city in Bremer County, Iowa.
Tonight
63°F
Chance Showers And Thunderstorms then Patchy Fog
A chance of showers and thunderstorms before midnight, then patchy fog and showers and thunderstorms. Some of the storms could produce heavy rain. Cloudy. Low around 63, with temperatures rising to around 65 overnight. Southeast wind 10 to 15 mph, with gusts as high as 22 mph. Chance of precipitation is 80%. New rainfall amounts between 1 and 2 inches possible.
7-day forecast for Sumner
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 63°F | Chance Showers And Thunderstorms then Patchy Fog | 10 to 15 mph SE | 82% |
| Saturday | 75°F | Patchy Fog | 9 mph SSW | 65% |
| Saturday Night | 58°F | Chance Showers And Thunderstorms | 10 to 14 mph NNE | 43% |
| Sunday | 66°F | Chance Rain Showers | 15 to 18 mph NE | 41% |
| Sunday Night | 52°F | Slight Chance Rain Showers | 16 mph ENE | 16% |
| Monday | 60°F | Chance Rain Showers | 18 mph ENE | 48% |
| Monday Night | 47°F | Chance Rain Showers | 10 to 15 mph NE | 48% |
| Tuesday | 59°F | Chance Rain Showers then Partly Sunny | 12 mph ENE | 31% |
| Tuesday Night | 45°F | Partly Cloudy | 7 mph ENE | 3% |
| Wednesday | 64°F | Mostly Sunny | 7 mph ENE | 0% |
| Wednesday Night | 49°F | Partly Cloudy | 5 mph E | 3% |
| Thursday | 66°F | Partly Sunny | 5 mph ESE | 10% |
| Thursday Night | 51°F | Partly Cloudy | 3 mph ESE | 7% |
| Friday | 67°F | Mostly Sunny | 2 to 6 mph ENE | 6% |
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 Sep 19, 2026.