Denison, IA Weather & Growing Conditions
This Afternoon
72°F
Slight Chance Showers And Thunderstorms
A slight chance of showers and thunderstorms after 5pm. Mostly cloudy. High near 72, with temperatures falling to around 69 in the afternoon. North wind around 9 mph. Chance of precipitation is 20%.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 72°F | Slight Chance Showers And Thunderstorms | 9 mph N | 15% |
| Tonight | 59°F | Slight Chance Showers And Thunderstorms then Mostly Cloudy | 6 to 9 mph NNE | 15% |
| Sunday | 63°F | Chance Drizzle then Chance Rain Showers | 7 to 12 mph NE | 42% |
| Sunday Night | 53°F | Rain Showers Likely | 8 mph NE | 68% |
| Monday | 57°F | Rain Showers | 8 mph NE | 83% |
| Monday Night | 48°F | Rain Showers Likely then Mostly Cloudy | 2 to 7 mph NE | 73% |
| Tuesday | 60°F | Partly Sunny | 6 mph ENE | 3% |
| Tuesday Night | 45°F | Partly Cloudy | 3 mph E | 0% |
| Wednesday | 64°F | Mostly Sunny | 1 to 5 mph ESE | 2% |
| Wednesday Night | 51°F | Mostly Cloudy then Slight Chance Showers And Thunderstorms | 2 mph SE | 24% |
| Thursday | 66°F | Chance Showers And Thunderstorms | 2 to 7 mph SSE | 36% |
| Thursday Night | 56°F | Slight Chance Rain Showers | 3 mph SE | 24% |
| Friday | 69°F | Slight Chance Rain Showers | 1 to 5 mph ESE | 18% |
| Friday Night | 58°F | Mostly Cloudy then Chance Rain Showers | 3 mph SE | 26% |
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 Sep 20, 2026.