Alton, MO Weather & Growing Conditions
This Afternoon
100°F
Sunny
Sunny. High near 100, with temperatures falling to around 98 in the afternoon. Heat index values as high as 101. Southwest wind around 8 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 100°F | Sunny | 8 mph SW | 0% |
| Tonight | 69°F | Mostly Clear | 2 to 6 mph SW | 0% |
| Sunday | 99°F | Mostly Sunny | 2 to 7 mph W | 1% |
| Sunday Night | 68°F | Partly Cloudy then Slight Chance Rain Showers | 5 mph NW | 19% |
| Monday | 93°F | Chance Rain Showers then Chance Showers And Thunderstorms | 1 to 5 mph N | 43% |
| Monday Night | 63°F | Chance Showers And Thunderstorms then Partly Cloudy | 6 mph N | 43% |
| Tuesday | 84°F | Mostly Sunny | 8 mph N | 9% |
| Tuesday Night | 55°F | Partly Cloudy | 5 to 9 mph N | 5% |
| Wednesday | 82°F | Mostly Sunny | 6 mph N | 1% |
| Wednesday Night | 54°F | Mostly Clear | 5 mph NE | 0% |
| Thursday | 83°F | Sunny | 5 mph NE | 0% |
| Thursday Night | 56°F | Partly Cloudy | 3 mph NE | 1% |
| Friday | 85°F | Mostly Sunny | 2 to 6 mph NE | 3% |
| Friday Night | 57°F | Partly Cloudy | 5 mph NE | 3% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Alton, MO
Last spring frost
Apr 17
First fall frost
Oct 21
Growing season
187 days
Hardiness zone
7a
Explore more for Alton, MO: full frost dates · planting calendar · Missouri frost dates
Climate data from the nearest NOAA station, Alton, Mo (10.1 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.