Thornton, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Thornton, a city in Cerro Gordo County, Iowa.
Overnight
64°F
Showers And Thunderstorms Likely
Showers and thunderstorms likely before 1am, then patchy fog and showers and thunderstorms likely between 1am and 4am, then patchy fog and showers and thunderstorms likely. Some of the storms could produce heavy rain. Cloudy. Low around 64, with temperatures rising to around 66 overnight. Southeast wind around 9 mph. Chance of precipitation is 70%. New rainfall amounts between three quarters and one inch possible.
7-day forecast for Thornton
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 64°F | Showers And Thunderstorms Likely | 9 mph SE | 70% |
| Saturday | 73°F | Patchy Fog | 8 mph WNW | 48% |
| Saturday Night | 57°F | Slight Chance Rain Showers | 8 to 12 mph N | 23% |
| Sunday | 65°F | Slight Chance Rain Showers | 12 to 15 mph NE | 21% |
| Sunday Night | 51°F | Chance Rain Showers | 9 to 13 mph ENE | 25% |
| Monday | 60°F | Chance Rain Showers | 13 mph ENE | 52% |
| Monday Night | 47°F | Chance Rain Showers | 6 to 10 mph ENE | 49% |
| Tuesday | 60°F | Slight Chance Rain Showers then Partly Sunny | 8 mph ENE | 16% |
| Tuesday Night | 44°F | Partly Cloudy | 5 mph E | 1% |
| Wednesday | 64°F | Sunny | 3 mph ESE | 1% |
| Wednesday Night | 48°F | Partly Cloudy | 2 mph SE | 6% |
| Thursday | 66°F | Slight Chance Rain Showers | 3 mph SSE | 17% |
| Thursday Night | 51°F | Mostly Cloudy | 2 mph SSE | 7% |
| Friday | 67°F | Partly Sunny | 1 to 5 mph ESE | 8% |
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 Sep 19, 2026.