Mount Vernon, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Mount Vernon, a city in Jefferson County, Illinois.
Today
88°F
Sunny
Sunny, with a high near 88. Southeast wind around 2 mph.
7-day forecast for Mount Vernon
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 88°F | Sunny | 2 mph SE | 0% |
| Tonight | 64°F | Mostly Clear | 2 mph SSE | 0% |
| Wednesday | 90°F | Sunny | 1 to 5 mph S | 1% |
| Wednesday Night | 69°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 1 to 5 mph SSE | 17% |
| Thursday | 88°F | Chance Showers And Thunderstorms | 1 to 5 mph SSW | 41% |
| Thursday Night | 70°F | Chance Showers And Thunderstorms | 2 mph S | 60% |
| Friday | 88°F | Showers And Thunderstorms Likely then Chance Showers And Thunderstorms | 0 to 3 mph WSW | 60% |
| Friday Night | 69°F | Chance Showers And Thunderstorms | 1 mph WNW | 43% |
| Saturday | 89°F | Chance Showers And Thunderstorms | 2 mph SW | 43% |
| Saturday Night | 70°F | Partly Cloudy | 2 mph SSW | 13% |
| Sunday | 91°F | Mostly Sunny | 2 to 7 mph SSW | 8% |
| Sunday Night | 72°F | Mostly Clear | 6 mph SSW | 4% |
| Monday | 93°F | Sunny | 3 to 8 mph SSW | 6% |
| Monday Night | 73°F | Partly Cloudy | 7 mph SSW | 10% |
Forecast source: National Weather Service (api.weather.gov) for Mount Vernon (38.314, -88.917). Updated through the day.
Growing snapshot for Mount Vernon
Last spring frost
Apr 11
First fall frost
Oct 22
Growing season
193 days
Hardiness zone
6b
More local growing data for Mount Vernon: nearby ZIP 62864 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Mt Vernon 3 Ne, Il (2.9 mi from Mount Vernon). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.