Alton, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Alton, a city in Sioux County, Iowa.
This Afternoon
55°F
Rain Showers
Rain showers. Cloudy. High near 55, with temperatures falling to around 47 in the afternoon. North northwest wind around 15 mph, with gusts as high as 25 mph. Chance of precipitation is 90%. New rainfall amounts between a tenth and quarter of an inch possible.
7-day forecast for Alton
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 55°F | Rain Showers | 15 mph NNW | 90% |
| Tonight | 39°F | Rain Showers | 15 mph NW | 95% |
| Wednesday | 47°F | Rain Showers | 15 mph WNW | 78% |
| 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 | 59°F | Sunny | 5 mph WSW | 3% |
| Sunday Night | 38°F | Mostly Clear | 5 mph S | 0% |
| Monday | 61°F | Sunny | 5 to 10 mph WSW | 0% |
| Monday Night | 38°F | Mostly Clear | 5 mph NW | 0% |
Forecast source: National Weather Service (api.weather.gov) for Alton (42.988, -96.009). Updated through the day.
Growing snapshot for Alton
Last spring frost
Apr 30
First fall frost
Oct 3
Growing season
154 days
Hardiness zone
5a
More local growing data for Alton: nearby ZIP 51003 weather · frost dates · planting calendar · Iowa frost dates
Nearby towns & communities
Boyden
Chatsworth
Craig
Hawarden
Hospers
Hull
Ireton
Matlock
Maurice
Orange City
Rock Valley
Sheldon
Sioux Center
Struble
Climate data from the nearest NOAA station, Sioux Ctr 2 Se, Ia (9.6 mi from Alton). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.