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
Chance Showers And Thunderstorms
A chance of showers and thunderstorms. Mostly cloudy. Low around 64, with temperatures rising to around 66 overnight. South southwest wind around 8 mph. Chance of precipitation is 30%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Thornton
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 64°F | Chance Showers And Thunderstorms | 8 mph SSW | 26% |
| Tuesday | 74°F | Showers And Thunderstorms Likely | 9 mph NW | 61% |
| Tuesday Night | 56°F | Showers And Thunderstorms Likely | 2 to 7 mph NNW | 60% |
| Wednesday | 73°F | Mostly Sunny | 3 mph NNE | 6% |
| Wednesday Night | 53°F | Mostly Clear | 1 mph SE | 2% |
| Thursday | 79°F | Sunny | 1 to 5 mph S | 2% |
| Thursday Night | 59°F | Mostly Clear | 5 mph S | 1% |
| Friday | 82°F | Sunny | 5 to 12 mph S | 8% |
| Friday Night | 64°F | Slight Chance Showers And Thunderstorms | 6 to 9 mph S | 23% |
| Saturday | 85°F | Slight Chance Showers And Thunderstorms then Sunny | 6 to 12 mph S | 15% |
| Saturday Night | 68°F | Slight Chance Showers And Thunderstorms | 12 mph S | 29% |
| Sunday | 85°F | Chance Showers And Thunderstorms then Mostly Sunny | 10 mph SE | 29% |
| Sunday Night | 67°F | Slight Chance Showers And Thunderstorms | 6 to 9 mph SSE | 33% |
| Monday | 84°F | Chance Showers And Thunderstorms | 12 mph SE | 33% |
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 Aug 4, 2026.