Thornton, IA Weather & Growing Conditions
Today
73°F
Patchy Fog
Patchy fog and a chance of showers and thunderstorms. Mostly cloudy. High near 73, with temperatures falling to around 70 in the afternoon. Northwest wind around 8 mph. Chance of precipitation is 50%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 73°F | Patchy Fog | 8 mph NW | 46% |
| Tonight | 57°F | Slight Chance Rain Showers | 8 to 12 mph N | 23% |
| Sunday | 65°F | Slight Chance Rain Showers then Slight Chance Drizzle | 12 to 15 mph NE | 16% |
| Sunday Night | 51°F | Chance Rain Showers | 12 mph ENE | 29% |
| Monday | 61°F | Chance Rain Showers | 12 mph ENE | 45% |
| Monday Night | 46°F | Chance Rain Showers | 5 to 9 mph ENE | 37% |
| Tuesday | 60°F | Mostly Sunny | 5 to 8 mph ENE | 10% |
| Tuesday Night | 43°F | Partly Cloudy | 2 to 6 mph E | 1% |
| Wednesday | 64°F | Sunny | 5 mph E | 1% |
| Wednesday Night | 47°F | Partly Cloudy | 2 mph ESE | 7% |
| Thursday | 65°F | Partly Sunny | 1 to 5 mph SE | 10% |
| Thursday Night | 50°F | Mostly Cloudy | 2 mph ESE | 4% |
| Friday | 68°F | Mostly Sunny | 1 to 5 mph SE | 6% |
| Friday Night | 52°F | Mostly Cloudy | 3 mph SE | 12% |
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 Sep 19, 2026.