Alton, IA Weather & Growing Conditions
Tonight
40°F
Rain Showers
Rain showers. Cloudy. Low around 40, with temperatures rising to around 43 overnight. Northwest wind 15 to 20 mph, with gusts as high as 30 mph. Chance of precipitation is 100%. New rainfall amounts between a quarter and half of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 40°F | Rain Showers | 15 to 20 mph NW | 95% |
| Wednesday | 47°F | Rain Showers | 15 mph WNW | 79% |
| Wednesday Night | 38°F | Chance Rain Showers | 10 to 15 mph NW | 50% |
| Thursday | 48°F | Chance Rain Showers then Mostly Cloudy | 10 to 15 mph NNW | 26% |
| Thursday Night | 33°F | Mostly Cloudy | 0 to 10 mph N | 0% |
| Friday | 48°F | Partly Sunny | 0 mph | 0% |
| Friday Night | 31°F | Mostly Cloudy | 0 mph | 1% |
| Saturday | 55°F | Mostly Sunny | 0 to 5 mph SW | 2% |
| Saturday Night | 35°F | Mostly Clear | 5 mph W | 5% |
| Sunday | 58°F | Sunny | 5 mph WSW | 3% |
| Sunday Night | 38°F | Mostly Clear | 5 mph SSW | 0% |
| Monday | 61°F | Sunny | 5 to 10 mph WSW | 0% |
| Monday Night | 38°F | Mostly Clear | 5 mph NW | 0% |
| Tuesday | 58°F | Mostly Sunny | 5 mph WSW | 1% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Alton, IA
Last spring frost
Apr 30
First fall frost
Oct 3
Growing season
154 days
Hardiness zone
5a
Explore more for Alton, IA: full frost dates · planting calendar · Iowa frost dates
Climate data from the nearest NOAA station, Sioux Ctr 2 Se, Ia (9.6 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.