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
Chance Showers And Thunderstorms
A chance of showers and thunderstorms before 1pm, then patchy smoke and a chance of showers and thunderstorms between 1pm and 2pm, then patchy smoke and showers and thunderstorms likely between 2pm and 4pm, then patchy smoke and a chance of showers and thunderstorms between 4pm and 5pm, then patchy smoke and a slight chance of showers and thunderstorms. Mostly cloudy. High near 74, with temperatures falling to around 72 in the afternoon. North wind around 14 mph, with gusts as high as 22 mph. Chance of precipitation is 70%. New rainfall amounts between a tenth and quarter of an inch possible.
7-day forecast for Onawa
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 74°F | Chance Showers And Thunderstorms | 14 mph N | 71% |
| Tonight | 58°F | Patchy Smoke | 2 to 10 mph NNE | 47% |
| Wednesday | 74°F | Patchy Smoke | 5 mph ENE | 18% |
| Wednesday Night | 54°F | Mostly Clear | 1 to 5 mph ESE | 1% |
| Thursday | 80°F | Sunny | 1 to 8 mph SSE | 1% |
| Thursday Night | 62°F | Mostly Clear | 5 to 8 mph SSE | 3% |
| Friday | 86°F | Sunny | 5 to 10 mph S | 3% |
| Friday Night | 66°F | Mostly Clear | 5 to 9 mph S | 8% |
| Saturday | 90°F | Sunny | 5 to 17 mph S | 3% |
| Saturday Night | 70°F | Mostly Clear | 10 to 17 mph S | 13% |
| Sunday | 90°F | Mostly Sunny | 9 to 13 mph SSE | 10% |
| Sunday Night | 71°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 10 to 15 mph SSE | 17% |
| Monday | 90°F | Slight Chance Showers And Thunderstorms then Mostly Sunny | 10 to 17 mph SE | 17% |
| Monday Night | 71°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 10 to 17 mph E | 17% |
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 Aug 4, 2026.