Johnston City, IL Weather & Growing Conditions
Today
99°F
Sunny
Sunny. High near 99, with temperatures falling to around 97 in the afternoon. West southwest wind around 8 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 99°F | Sunny | 8 mph WSW | 2% |
| Tonight | 73°F | Mostly Clear | 5 mph SSW | 2% |
| Sunday | 97°F | Mostly Sunny | 3 to 8 mph WSW | 0% |
| Sunday Night | 69°F | Mostly Cloudy then Chance Showers And Thunderstorms | 6 mph N | 29% |
| Monday | 86°F | Showers And Thunderstorms Likely | 6 to 12 mph NNE | 61% |
| Monday Night | 61°F | Showers And Thunderstorms Likely then Chance Showers And Thunderstorms | 6 to 12 mph NNE | 61% |
| Tuesday | 76°F | Chance Showers And Thunderstorms | 8 to 13 mph N | 30% |
| Tuesday Night | 56°F | Slight Chance Rain Showers then Partly Cloudy | 5 to 13 mph N | 16% |
| Wednesday | 76°F | Mostly Sunny | 7 to 12 mph N | 2% |
| Wednesday Night | 56°F | Partly Cloudy | 2 to 12 mph N | 0% |
| Thursday | 77°F | Mostly Sunny | 3 to 10 mph N | 2% |
| Thursday Night | 58°F | Partly Cloudy | 2 to 8 mph NNE | 4% |
| Friday | 78°F | Mostly Sunny | 3 to 10 mph NNE | 4% |
| Friday Night | 57°F | Partly Cloudy | 3 to 8 mph NE | 2% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Johnston City, IL
Last spring frost
Apr 4
First fall frost
Oct 28
Growing season
206 days
Hardiness zone
7a
Explore more for Johnston City, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Benton 2 N, Il (14.4 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.