Union, IL Weather & Growing Conditions
This Afternoon
71°F
Showers And Thunderstorms
Showers and thunderstorms. Cloudy, with a high near 71. South southeast wind around 5 mph, with gusts as high as 15 mph. Chance of precipitation is 80%. New rainfall amounts between three quarters and one inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 71°F | Showers And Thunderstorms | 5 mph SSE | 83% |
| Tonight | 62°F | Showers And Thunderstorms | 5 to 10 mph ENE | 93% |
| Sunday | 68°F | Showers And Thunderstorms Likely | 10 to 15 mph NE | 55% |
| Sunday Night | 55°F | Slight Chance Rain Showers | 15 mph NE | 18% |
| Monday | 63°F | Chance Rain Showers | 15 mph ENE | 29% |
| Monday Night | 50°F | Slight Chance Rain Showers then Mostly Cloudy | 10 to 15 mph NE | 17% |
| Tuesday | 62°F | Mostly Cloudy | 10 to 15 mph NE | 14% |
| Tuesday Night | 49°F | Partly Cloudy | 5 to 15 mph NE | 7% |
| Wednesday | 64°F | Partly Sunny | 5 to 15 mph NE | 6% |
| Wednesday Night | 50°F | Mostly Cloudy | 5 to 10 mph NE | 2% |
| Thursday | 67°F | Partly Sunny | 5 to 10 mph NE | 4% |
| Thursday Night | 51°F | Partly Cloudy | 0 to 5 mph NE | 4% |
| Friday | 70°F | Mostly Sunny | 0 to 5 mph NE | 4% |
| Friday Night | 51°F | Partly Cloudy | 0 to 5 mph ENE | 4% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Union, IL
Last spring frost
Apr 28
First fall frost
Oct 12
Growing season
166 days
Hardiness zone
5b
Explore more for Union, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Marengo, Il (5.3 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.