Onawa, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Onawa, a city in Monona County, Iowa.
This Afternoon
56°F
Rain Showers
Rain showers. Cloudy. High near 56, with temperatures falling to around 52 in the afternoon. North northwest wind around 18 mph, with gusts as high as 32 mph. Chance of precipitation is 80%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Onawa
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 56°F | Rain Showers | 18 mph NNW | 84% |
| Tonight | 40°F | Rain Showers | 14 to 17 mph NW | 89% |
| Wednesday | 50°F | Chance Rain Showers | 13 to 16 mph WNW | 34% |
| Wednesday Night | 38°F | Cloudy then Chance Rain Showers | 12 mph NW | 42% |
| Thursday | 50°F | Chance Rain Showers | 9 to 13 mph NNW | 33% |
| Thursday Night | 34°F | Mostly Cloudy | 3 to 8 mph NNW | 2% |
| Friday | 51°F | Partly Sunny | 3 mph N | 0% |
| Friday Night | 32°F | Mostly Cloudy | 2 mph SSE | 0% |
| Saturday | 59°F | Mostly Sunny | 5 mph SW | 3% |
| Saturday Night | 35°F | Mostly Clear | 3 mph W | 5% |
| Sunday | 62°F | Sunny | 2 to 6 mph WSW | 2% |
| Sunday Night | 39°F | Mostly Clear | 6 mph S | 0% |
| Monday | 64°F | Sunny | 6 to 9 mph WSW | 0% |
| Monday Night | 39°F | Mostly Clear | 6 mph NW | 0% |
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 Nov 4, 2026.