Onawa, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Onawa, a city in Monona County, Iowa.
Today
74°F
Mostly Cloudy
Mostly cloudy, with a high near 74. North northwest wind 7 to 10 mph, with gusts as high as 16 mph. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Onawa
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 74°F | Mostly Cloudy | 7 to 10 mph NNW | 9% |
| Tonight | 59°F | Slight Chance Rain Showers | 10 mph N | 15% |
| Sunday | 64°F | Chance Rain Showers | 12 mph NNE | 38% |
| Sunday Night | 55°F | Chance Rain Showers | 7 to 10 mph NE | 53% |
| Monday | 60°F | Rain Showers Likely | 9 mph ENE | 62% |
| Monday Night | 50°F | Chance Rain Showers then Mostly Cloudy | 3 to 9 mph ENE | 41% |
| Tuesday | 62°F | Partly Sunny | 3 to 7 mph E | 8% |
| Tuesday Night | 46°F | Partly Cloudy | 2 to 6 mph ESE | 1% |
| Wednesday | 65°F | Mostly Sunny | 2 to 7 mph SE | 4% |
| Wednesday Night | 52°F | Partly Cloudy then Chance Rain Showers | 6 mph SE | 31% |
| Thursday | 66°F | Chance Rain Showers | 5 to 8 mph SE | 31% |
| Thursday Night | 55°F | Slight Chance Rain Showers then Slight Chance Showers And Thunderstorms | 6 mph SE | 17% |
| Friday | 69°F | Slight Chance Showers And Thunderstorms | 3 to 8 mph SE | 17% |
| Friday Night | 56°F | Mostly Cloudy then Slight Chance Rain Showers | 7 mph SE | 24% |
Forecast source: National Weather Service (api.weather.gov) for Onawa (42.026, -96.091). Updated through the day.
Growing snapshot for Onawa
Last spring frost
May 1
First fall frost
Oct 3
Growing season
154 days
Hardiness zone
5a
More local growing data for Onawa: nearby ZIP 51040 weather · frost dates · planting calendar · Iowa frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Onawa 3Nw, Ia (3.9 mi from Onawa). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.