Thornburg, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Thornburg, a city in Keokuk County, Iowa.
Today
50°F
Slight Chance Drizzle
A slight chance of drizzle. Cloudy, with a high near 50. West wind around 15 mph, with gusts as high as 25 mph.
7-day forecast for Thornburg
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 50°F | Slight Chance Drizzle | 15 mph W | 13% |
| Tonight | 45°F | Slight Chance Rain Showers | 10 to 15 mph W | 17% |
| Thursday | 51°F | Chance Rain Showers | 10 to 15 mph NW | 33% |
| Thursday Night | 39°F | Mostly Cloudy | 10 mph N | 12% |
| Friday | 50°F | Mostly Sunny | 5 to 10 mph N | 1% |
| Friday Night | 30°F | Partly Cloudy | 0 to 5 mph N | 0% |
| Saturday | 52°F | Mostly Sunny | 0 to 5 mph W | 0% |
| Saturday Night | 34°F | Mostly Clear | 0 to 5 mph W | 1% |
| Sunday | 57°F | Sunny | 5 mph W | 1% |
| Sunday Night | 35°F | Clear | 5 mph SW | 0% |
| Monday | 64°F | Sunny | 5 to 10 mph SW | 0% |
| Monday Night | 40°F | Mostly Clear | 5 mph W | 0% |
| Tuesday | 64°F | Sunny | 5 mph NW | 0% |
| Tuesday Night | 41°F | Partly Cloudy | 0 to 5 mph NE | 1% |
Forecast source: National Weather Service (api.weather.gov) for Thornburg (41.456, -92.332). Updated through the day.
Growing snapshot for Thornburg
Last spring frost
Apr 24
First fall frost
Oct 15
Growing season
172 days
Hardiness zone
5b
More local growing data for Thornburg: nearby ZIP 50255 weather · frost dates · planting calendar · Iowa frost dates
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Climate data from the nearest NOAA station, Sigourney, Ia (9.8 mi from Thornburg). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.