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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

WhenTempForecastWindPrecip
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.