Thornton, IA Weather & Growing Conditions
Today
74°F
Showers And Thunderstorms Likely
Showers and thunderstorms likely. Mostly cloudy. High near 74, with temperatures falling to around 72 in the afternoon. North northwest wind 7 to 10 mph. Chance of precipitation is 70%. New rainfall amounts between a tenth and quarter of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 74°F | Showers And Thunderstorms Likely | 7 to 10 mph NNW | 72% |
| Tonight | 56°F | Showers And Thunderstorms Likely | 3 to 8 mph NNW | 60% |
| Wednesday | 73°F | Partly Sunny | 5 mph NNE | 6% |
| Wednesday Night | 53°F | Mostly Clear | 2 mph SE | 2% |
| Thursday | 79°F | Sunny | 1 to 5 mph S | 2% |
| Thursday Night | 59°F | Mostly Clear | 6 mph S | 1% |
| Friday | 82°F | Sunny | 5 to 12 mph S | 8% |
| Friday Night | 64°F | Slight Chance Showers And Thunderstorms | 7 to 10 mph S | 23% |
| Saturday | 85°F | Slight Chance Showers And Thunderstorms then Sunny | 6 to 10 mph S | 15% |
| Saturday Night | 68°F | Slight Chance Showers And Thunderstorms | 9 to 13 mph SSE | 29% |
| Sunday | 86°F | Chance Showers And Thunderstorms then Mostly Sunny | 12 mph SE | 29% |
| Sunday Night | 67°F | Slight Chance Showers And Thunderstorms | 9 mph SSE | 33% |
| Monday | 84°F | Chance Showers And Thunderstorms | 12 mph SE | 33% |
| Monday Night | 67°F | Slight Chance Showers And Thunderstorms | 9 to 13 mph ENE | 34% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Thornton, IA
Last spring frost
May 3
First fall frost
Oct 1
Growing season
150 days
Hardiness zone
5a
Explore more for Thornton, IA: full frost dates · planting calendar · Iowa frost dates
Climate data from the nearest NOAA station, Mason City Muni Ap, Ia (15.3 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.