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Denison, IA Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for Denison, a city in Crawford County, Iowa.

Overnight
66°F
Patchy Fog
Patchy fog and a chance of showers and thunderstorms. Cloudy. Low around 66, with temperatures rising to around 69 overnight. West northwest wind around 6 mph. Chance of precipitation is 50%. New rainfall amounts between a tenth and quarter of an inch possible.

7-day forecast for Denison

WhenTempForecastWindPrecip
Overnight 66°F Patchy Fog 6 mph WNW 51%
Saturday 75°F Patchy Fog then Mostly Cloudy 3 to 7 mph NNW 49%
Saturday Night 59°F Slight Chance Rain Showers then Slight Chance Drizzle 8 mph NNE 16%
Sunday 63°F Slight Chance Drizzle then Chance Rain Showers 8 to 12 mph NE 34%
Sunday Night 54°F Chance Rain Showers 8 mph ENE 45%
Monday 59°F Rain Showers Likely 8 mph ENE 58%
Monday Night 49°F Chance Rain Showers then Mostly Cloudy 2 to 7 mph ENE 45%
Tuesday 60°F Partly Sunny 2 to 6 mph ENE 8%
Tuesday Night 45°F Partly Cloudy 3 mph ESE 1%
Wednesday 64°F Mostly Sunny 1 to 5 mph SE 2%
Wednesday Night 50°F Partly Cloudy then Slight Chance Rain Showers 2 mph SE 23%
Thursday 65°F Slight Chance Rain Showers 1 to 6 mph SE 23%
Thursday Night 54°F Mostly Cloudy then Slight Chance Rain Showers 3 mph SE 15%
Friday 68°F Slight Chance Rain Showers then Mostly Cloudy 1 to 6 mph SE 15%

Forecast source: National Weather Service (api.weather.gov) for Denison (42.016, -95.353). Updated through the day.

Growing snapshot for Denison

Last spring frost
Apr 27
First fall frost
Oct 11
Growing season
166 days
Hardiness zone
5a

More local growing data for Denison: nearby ZIP 51442 weather · frost dates · planting calendar · Iowa frost dates

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Climate data from the nearest NOAA station, Denison, Ia (1.5 mi from Denison). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.