Union, IL Weather & Growing Conditions
This Afternoon
68°F
Rain Showers
Rain showers. Mostly cloudy. High near 68, with temperatures falling to around 65 in the afternoon. South wind around 15 mph, with gusts as high as 30 mph. Chance of precipitation is 80%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 68°F | Rain Showers | 15 mph S | 75% |
| Tonight | 58°F | Rain Showers | 15 mph S | 88% |
| Wednesday | 62°F | Rain Showers Likely | 15 mph SSW | 57% |
| Wednesday Night | 47°F | Chance Rain Showers | 15 mph SW | 28% |
| Thursday | 55°F | Chance Rain Showers | 10 to 15 mph WSW | 46% |
| Thursday Night | 41°F | Chance Rain Showers | 5 to 10 mph NW | 49% |
| Friday | 51°F | Slight Chance Rain Showers then Mostly Cloudy | 10 mph N | 20% |
| Friday Night | 34°F | Partly Cloudy | 0 to 5 mph NNW | 3% |
| Saturday | 51°F | Mostly Sunny | 0 to 5 mph WNW | 3% |
| Saturday Night | 33°F | Partly Cloudy | 0 to 5 mph WSW | 6% |
| Sunday | 56°F | Mostly Sunny then Slight Chance Rain | 5 to 10 mph W | 17% |
| Sunday Night | 34°F | Mostly Clear | 0 to 5 mph W | 6% |
| Monday | 60°F | Sunny | 5 to 10 mph WSW | 2% |
| Monday Night | 39°F | Mostly Clear | 5 mph W | 2% |
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 Nov 4, 2026.