Thornton, IA Weather & Growing Conditions
Overnight
43°F
Chance Rain Showers
A chance of rain showers. Cloudy. Low around 43, with temperatures rising to around 45 overnight. West northwest wind around 14 mph, with gusts as high as 21 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 |
|---|---|---|---|---|
| Overnight | 43°F | Chance Rain Showers | 14 mph WNW | 54% |
| Wednesday | 49°F | Chance Rain Showers | 14 to 17 mph WNW | 48% |
| Wednesday Night | 41°F | Rain Showers Likely | 13 mph WNW | 65% |
| Thursday | 50°F | Chance Rain Showers then Cloudy | 10 to 15 mph NNW | 45% |
| Thursday Night | 33°F | Mostly Cloudy | 5 to 9 mph N | 10% |
| Friday | 47°F | Mostly Sunny | 2 to 6 mph NNE | 2% |
| Friday Night | 27°F | Partly Cloudy | 1 mph NNW | 0% |
| Saturday | 50°F | Mostly Sunny | 1 to 5 mph SW | 0% |
| Saturday Night | 33°F | Mostly Clear | 5 mph W | 2% |
| Sunday | 56°F | Sunny | 6 mph W | 2% |
| Sunday Night | 34°F | Mostly Clear | 5 mph SW | 0% |
| Monday | 61°F | Sunny | 5 to 10 mph SW | 0% |
| Monday Night | 38°F | Mostly Clear | 5 mph WNW | 0% |
| Tuesday | 60°F | Mostly Sunny | 3 mph NW | 0% |
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 Nov 4, 2026.