Alton, IA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Alton, a city in Sioux County, Iowa.
Today
73°F
Patchy Smoke
A chance of rain showers and patchy smoke before 10am, then patchy smoke and showers and thunderstorms likely between 10am and 3pm, then a chance of showers and thunderstorms between 3pm and 4pm, then a chance of showers and thunderstorms between 4pm and 5pm, then patchy smoke and a chance of showers and thunderstorms. Mostly cloudy, with a high near 73. North wind 5 to 10 mph. Chance of precipitation is 60%. New rainfall amounts between a quarter and half of an inch possible.
7-day forecast for Alton
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 73°F | Patchy Smoke | 5 to 10 mph N | 59% |
| Tonight | 54°F | Patchy Smoke then Mostly Cloudy | 0 to 5 mph NNW | 55% |
| Wednesday | 75°F | Mostly Sunny | 0 to 5 mph ESE | 1% |
| Wednesday Night | 53°F | Mostly Clear | 0 to 5 mph SSE | 0% |
| Thursday | 82°F | Mostly Sunny | 0 to 10 mph S | 0% |
| Thursday Night | 61°F | Mostly Clear | 5 to 10 mph S | 3% |
| Friday | 86°F | Sunny | 5 to 10 mph SSW | 4% |
| Friday Night | 65°F | Mostly Clear | 5 to 10 mph S | 12% |
| Saturday | 90°F | Sunny | 5 to 15 mph S | 5% |
| Saturday Night | 67°F | Slight Chance Showers And Thunderstorms | 10 to 15 mph SSE | 20% |
| Sunday | 88°F | Slight Chance Showers And Thunderstorms then Mostly Sunny | 10 mph SE | 15% |
| Sunday Night | 68°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 10 to 15 mph ESE | 18% |
| Monday | 88°F | Slight Chance Showers And Thunderstorms then Partly Sunny | 10 to 15 mph E | 18% |
| Monday Night | 67°F | Chance Showers And Thunderstorms | 10 to 15 mph ENE | 27% |
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 Aug 4, 2026.