Denison, IA Weather & Growing Conditions
Tonight
39°F
Rain Showers Likely
Rain showers likely. Cloudy. Low around 39, with temperatures rising to around 43 overnight. Northwest wind 9 to 16 mph, with gusts as high as 23 mph. Chance of precipitation is 60%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 39°F | Rain Showers Likely | 9 to 16 mph NW | 58% |
| Wednesday | 48°F | Chance Rain Showers | 10 to 14 mph WNW | 42% |
| Wednesday Night | 38°F | Cloudy then Chance Rain Showers | 6 to 10 mph WNW | 54% |
| Thursday | 51°F | Chance Rain Showers | 9 mph NNW | 53% |
| Thursday Night | 34°F | Mostly Cloudy | 2 to 6 mph N | 4% |
| Friday | 50°F | Partly Sunny | 2 mph N | 0% |
| Friday Night | 32°F | Mostly Cloudy | 0 mph | 0% |
| Saturday | 56°F | Mostly Sunny | 0 to 5 mph WSW | 2% |
| Saturday Night | 35°F | Mostly Clear | 2 mph W | 4% |
| Sunday | 62°F | Sunny | 1 to 5 mph WSW | 5% |
| Sunday Night | 38°F | Mostly Clear | 5 mph SSW | 0% |
| Monday | 64°F | Sunny | 5 to 8 mph WSW | 0% |
| Monday Night | 39°F | Mostly Clear | 1 to 5 mph NW | 0% |
| Tuesday | 62°F | Mostly Sunny | 1 to 5 mph W | 0% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Denison, IA
Last spring frost
Apr 27
First fall frost
Oct 11
Growing season
166 days
Hardiness zone
5a
Explore more for Denison, IA: full frost dates · planting calendar · Iowa frost dates
Climate data from the nearest NOAA station, Denison, Ia (1.5 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.