Alton, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Alton, a city in Sioux County, Iowa.
Overnight
63°F
Areas Of Fog
Areas of fog and a slight chance of showers and thunderstorms. Cloudy. Low around 63, with temperatures rising to around 66 overnight. North wind around 5 mph. Chance of precipitation is 20%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Alton
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 63°F | Areas Of Fog | 5 mph N | 23% |
| Saturday | 69°F | Areas Of Fog then Cloudy | 5 to 10 mph N | 33% |
| Saturday Night | 56°F | Cloudy | 10 mph NNE | 10% |
| Sunday | 65°F | Cloudy then Slight Chance Rain Showers | 10 to 15 mph NE | 21% |
| Sunday Night | 52°F | Rain Showers Likely | 10 mph ENE | 58% |
| Monday | 60°F | Rain Showers Likely | 10 mph ENE | 58% |
| Monday Night | 47°F | Chance Rain Showers then Mostly Cloudy | 5 to 10 mph ENE | 40% |
| Tuesday | 62°F | Partly Sunny | 5 to 10 mph E | 3% |
| Tuesday Night | 44°F | Partly Cloudy | 5 mph ESE | 2% |
| Wednesday | 66°F | Mostly Sunny | 5 to 10 mph SE | 4% |
| Wednesday Night | 50°F | Partly Cloudy then Chance Rain Showers | 5 mph SE | 25% |
| Thursday | 67°F | Chance Rain Showers | 5 to 10 mph SSE | 25% |
| Thursday Night | 53°F | Mostly Cloudy then Slight Chance Rain Showers | 5 mph SE | 15% |
| Friday | 70°F | Slight Chance Rain Showers | 5 to 10 mph SE | 15% |
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 Sep 19, 2026.