Thornburg, IA Weather & Growing Conditions
Today
50°F
Slight Chance Rain Showers then Cloudy
A slight chance of rain showers before 9am. Cloudy, with a high near 50. West wind around 15 mph, with gusts as high as 25 mph. Chance of precipitation is 20%.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 50°F | Slight Chance Rain Showers then Cloudy | 15 mph W | 16% |
| Tonight | 43°F | Cloudy | 10 to 15 mph W | 11% |
| Thursday | 54°F | Rain Showers Likely | 10 to 15 mph NW | 62% |
| Thursday Night | 39°F | Mostly Cloudy | 10 mph N | 12% |
| Friday | 49°F | Mostly Sunny | 5 to 10 mph N | 1% |
| Friday Night | 29°F | Partly Cloudy | 0 to 5 mph N | 0% |
| Saturday | 51°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 | 63°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). Updated through the day.
Growing snapshot for Thornburg, IA
Last spring frost
Apr 24
First fall frost
Oct 15
Growing season
172 days
Hardiness zone
5b
Explore more for Thornburg, IA: full frost dates · planting calendar · Iowa frost dates
Climate data from the nearest NOAA station, Sigourney, Ia (9.7 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.