Thornburg, IA Weather & Growing Conditions
Today
81°F
Chance Showers And Thunderstorms
A chance of showers and thunderstorms before 1pm, then a chance of showers and thunderstorms between 1pm and 4pm, then a chance of showers and thunderstorms. Partly sunny, with a high near 81. Southwest wind 5 to 10 mph. Chance of precipitation is 50%.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 81°F | Chance Showers And Thunderstorms | 5 to 10 mph SW | 54% |
| Tonight | 63°F | Chance Showers And Thunderstorms then Showers And Thunderstorms | 5 to 10 mph NW | 78% |
| Sunday | 68°F | Showers And Thunderstorms then Slight Chance Showers And Thunderstorms | 10 to 15 mph NE | 77% |
| Sunday Night | 57°F | Showers And Thunderstorms Likely | 15 mph NE | 58% |
| Monday | 62°F | Rain Showers Likely | 15 mph NE | 58% |
| Monday Night | 51°F | Chance Rain Showers | 10 to 15 mph NE | 47% |
| Tuesday | 60°F | Chance Rain Showers then Partly Sunny | 10 mph NE | 32% |
| Tuesday Night | 46°F | Mostly Clear | 5 to 10 mph NE | 4% |
| Wednesday | 65°F | Sunny | 5 mph NE | 0% |
| Wednesday Night | 50°F | Partly Cloudy | 5 mph NE | 2% |
| Thursday | 66°F | Partly Sunny | 5 mph E | 8% |
| Thursday Night | 54°F | Partly Cloudy | 0 to 5 mph E | 6% |
| Friday | 69°F | Mostly Sunny | 5 mph E | 6% |
| Friday Night | 55°F | Partly Cloudy | 5 mph E | 8% |
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 Sep 19, 2026.