Thornton, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Thornton, a city in Cerro Gordo County, Iowa.
This Afternoon
46°F
Slight Chance Rain Showers
A slight chance of rain showers. Cloudy, with a high near 46. West wind around 15 mph, with gusts as high as 24 mph. Chance of precipitation is 20%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Thornton
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 46°F | Slight Chance Rain Showers | 15 mph W | 24% |
| Tonight | 40°F | Chance Rain Showers | 13 mph WNW | 49% |
| Thursday | 48°F | Slight Chance Rain Showers then Cloudy | 12 to 16 mph NNW | 24% |
| Thursday Night | 31°F | Mostly Cloudy | 5 to 9 mph N | 2% |
| Friday | 44°F | Mostly Sunny | 5 mph NNE | 0% |
| Friday Night | 25°F | Partly Cloudy | 1 mph NNW | 0% |
| Saturday | 50°F | Mostly Sunny | 1 to 6 mph SW | 0% |
| Saturday Night | 32°F | Mostly Clear | 5 mph W | 0% |
| Sunday | 57°F | Sunny | 5 mph W | 0% |
| Sunday Night | 35°F | Clear | 3 mph SW | 0% |
| Monday | 63°F | Sunny | 5 to 10 mph SW | 0% |
| Monday Night | 37°F | Mostly Clear | 2 to 6 mph WNW | 0% |
| Tuesday | 59°F | Mostly Sunny | 5 mph NNW | 1% |
| Tuesday Night | 36°F | Partly Cloudy | 2 mph NNW | 1% |
Forecast source: National Weather Service (api.weather.gov) for Thornton (42.944, -93.387). Updated through the day.
Growing snapshot for Thornton
Last spring frost
May 3
First fall frost
Oct 1
Growing season
150 days
Hardiness zone
5a
More local growing data for Thornton: nearby ZIP 50479 weather · frost dates · planting calendar · Iowa frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Mason City Muni Ap, Ia (15.3 mi from Thornton). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.