Herculaneum, MO Weather & Growing Conditions
This Afternoon
99°F
Mostly Sunny
Mostly sunny, with a high near 99. Heat index values as high as 103. Southwest wind around 5 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 99°F | Mostly Sunny | 5 mph SW | 1% |
| Tonight | 71°F | Partly Cloudy | 3 mph SW | 2% |
| Sunday | 94°F | Partly Sunny | 5 mph W | 3% |
| Sunday Night | 65°F | Chance Showers And Thunderstorms then Showers And Thunderstorms Likely | 5 mph NE | 62% |
| Monday | 82°F | Showers And Thunderstorms Likely | 2 to 6 mph NE | 59% |
| Monday Night | 59°F | Showers And Thunderstorms Likely | 3 to 7 mph NE | 59% |
| Tuesday | 73°F | Slight Chance Rain Showers then Mostly Cloudy | 5 to 8 mph N | 23% |
| Tuesday Night | 53°F | Mostly Cloudy | 2 to 8 mph N | 1% |
| Wednesday | 74°F | Mostly Sunny | 3 to 7 mph N | 0% |
| Wednesday Night | 53°F | Partly Cloudy | 0 to 6 mph N | 0% |
| Thursday | 76°F | Mostly Sunny | 0 to 5 mph N | 2% |
| Thursday Night | 56°F | Mostly Cloudy | 0 to 3 mph NE | 5% |
| Friday | 79°F | Slight Chance Rain Showers | 1 to 5 mph NE | 18% |
| Friday Night | 56°F | Slight Chance Rain Showers then Mostly Cloudy | 3 mph NE | 18% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Herculaneum, MO
Last spring frost
Apr 9
First fall frost
Oct 26
Growing season
197 days
Hardiness zone
7a
Explore more for Herculaneum, MO: full frost dates · planting calendar · Missouri frost dates
Climate data from the nearest NOAA station, Festus, Mo (2 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 20, 2026.