Denison, IA Weather & Growing Conditions
Today
75°F
Showers And Thunderstorms
Showers and thunderstorms. Partly sunny. High near 75, with temperatures falling to around 73 in the afternoon. North northeast wind around 9 mph. Chance of precipitation is 80%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 75°F | Showers And Thunderstorms | 9 mph NNE | 75% |
| Tonight | 57°F | Showers And Thunderstorms Likely | 2 to 8 mph NE | 67% |
| Wednesday | 73°F | Chance Showers And Thunderstorms | 6 mph ENE | 33% |
| Wednesday Night | 53°F | Mostly Clear | 0 to 3 mph E | 2% |
| Thursday | 80°F | Sunny | 0 to 5 mph SE | 1% |
| Thursday Night | 61°F | Mostly Clear | 5 mph SSE | 2% |
| Friday | 85°F | Mostly Sunny | 2 to 8 mph S | 3% |
| Friday Night | 65°F | Mostly Clear | 3 to 7 mph S | 8% |
| Saturday | 89°F | Mostly Sunny | 2 to 13 mph S | 4% |
| Saturday Night | 69°F | Mostly Clear | 8 to 13 mph S | 14% |
| Sunday | 89°F | Mostly Sunny | 10 mph SSE | 14% |
| Sunday Night | 69°F | Chance Showers And Thunderstorms | 10 mph SSE | 27% |
| Monday | 89°F | Chance Showers And Thunderstorms then Partly Sunny | 13 mph SSE | 27% |
| Monday Night | 70°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 9 to 14 mph ESE | 21% |
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 Aug 4, 2026.