Alton, IA Weather & Growing Conditions
Tonight
63°F
Patchy Fog
A slight chance of showers and thunderstorms before midnight, then patchy fog between midnight and 1am, then patchy fog and a chance of showers and thunderstorms between 1am and 3am, then areas of fog and a chance of showers and thunderstorms between 3am and 4am, then patchy fog and a chance of showers and thunderstorms. Cloudy, with a low around 63. North wind 5 to 10 mph. Chance of precipitation is 30%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 63°F | Patchy Fog | 5 to 10 mph N | 34% |
| Saturday | 70°F | Patchy Fog then Cloudy | 5 to 10 mph N | 23% |
| Saturday Night | 57°F | Slight Chance Rain Showers then Cloudy | 10 mph NNE | 16% |
| Sunday | 65°F | Mostly Cloudy then Chance Rain Showers | 10 to 15 mph NE | 28% |
| Sunday Night | 53°F | Rain Showers Likely | 10 mph ENE | 61% |
| Monday | 59°F | Rain Showers Likely | 10 mph ENE | 61% |
| Monday Night | 48°F | Chance Rain Showers then Mostly Cloudy | 5 to 10 mph ENE | 39% |
| Tuesday | 61°F | Partly Sunny | 5 to 10 mph E | 9% |
| Tuesday Night | 46°F | Partly Cloudy | 5 mph ESE | 0% |
| Wednesday | 65°F | Mostly Sunny | 5 to 10 mph SE | 7% |
| Wednesday Night | 51°F | Mostly Cloudy then Chance Rain Showers | 5 mph SE | 33% |
| Thursday | 67°F | Chance Rain Showers | 5 mph SSE | 33% |
| Thursday Night | 53°F | Mostly Cloudy then Slight Chance Rain Showers | 0 to 5 mph SE | 16% |
| Friday | 68°F | Slight Chance Rain Showers then Partly Sunny | 5 to 10 mph SE | 16% |
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 Sep 19, 2026.