Thornton, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Thornton, a city in Cerro Gordo County, Iowa.
Tonight
43°F
Showers And Thunderstorms
Showers and thunderstorms. Cloudy. Low around 43, with temperatures rising to around 48 overnight. Northwest wind 7 to 12 mph. Chance of precipitation is 90%. New rainfall amounts between a quarter and half of an inch possible.
7-day forecast for Thornton
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 43°F | Showers And Thunderstorms | 7 to 12 mph NW | 90% |
| Wednesday | 50°F | Rain Showers Likely | 10 to 16 mph W | 70% |
| Wednesday Night | 40°F | Rain Showers | 9 to 13 mph W | 81% |
| Thursday | 49°F | Rain Showers Likely | 13 mph NNW | 63% |
| Thursday Night | 34°F | Slight Chance Rain Showers then Mostly Cloudy | 5 to 9 mph N | 15% |
| Friday | 48°F | Partly Sunny | 2 to 7 mph NNE | 2% |
| Friday Night | 29°F | Partly Cloudy | 1 mph NNE | 1% |
| Saturday | 53°F | Mostly Sunny | 0 to 6 mph SW | 1% |
| Saturday Night | 34°F | Mostly Clear | 3 mph W | 4% |
| Sunday | 58°F | Sunny | 3 to 7 mph W | 7% |
| Sunday Night | 35°F | Mostly Clear | 6 mph SW | 2% |
| Monday | 61°F | Mostly Sunny | 6 to 10 mph WSW | 0% |
| Monday Night | 38°F | Mostly Clear | 6 mph WNW | 1% |
| Tuesday | 59°F | Mostly Sunny | 6 mph WNW | 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.