Union, IL Weather & Growing Conditions
Today
83°F
Mostly Sunny
Mostly sunny, with a high near 83. South southwest wind 5 to 10 mph, with gusts as high as 20 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 83°F | Mostly Sunny | 5 to 10 mph SSW | 1% |
| Tonight | 66°F | Mostly Cloudy then Chance Showers And Thunderstorms | 0 to 5 mph SW | 62% |
| Wednesday | 77°F | Showers And Thunderstorms Likely | 0 to 5 mph WSW | 74% |
| Wednesday Night | 61°F | Showers And Thunderstorms | 0 to 5 mph NW | 78% |
| Thursday | 78°F | Chance Rain Showers then Slight Chance Showers And Thunderstorms | 0 to 5 mph NE | 50% |
| Thursday Night | 59°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 0 mph | 15% |
| Friday | 81°F | Mostly Sunny | 0 to 5 mph SE | 5% |
| Friday Night | 62°F | Mostly Clear | 0 to 5 mph SSW | 8% |
| Saturday | 83°F | Mostly Sunny | 0 to 10 mph SSW | 11% |
| Saturday Night | 68°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 5 mph SSW | 20% |
| Sunday | 84°F | Slight Chance Showers And Thunderstorms | 5 to 10 mph SW | 20% |
| Sunday Night | 68°F | Chance Showers And Thunderstorms | 5 to 10 mph SSW | 43% |
| Monday | 83°F | Chance Rain Showers | 5 mph SSW | 43% |
| Monday Night | 68°F | Chance Showers And Thunderstorms | 5 mph WNW | 45% |
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 Aug 4, 2026.