Union, IA Weather & Growing Conditions
Today
77°F
Chance Showers And Thunderstorms
A chance of showers and thunderstorms. Mostly cloudy. High near 77, with temperatures falling to around 75 in the afternoon. West southwest wind around 7 mph. Chance of precipitation is 40%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 77°F | Chance Showers And Thunderstorms | 7 mph WSW | 44% |
| Tonight | 59°F | Chance Showers And Thunderstorms | 9 mph N | 36% |
| Sunday | 66°F | Chance Rain Showers | 10 to 14 mph NE | 32% |
| Sunday Night | 54°F | Chance Rain Showers | 13 mph ENE | 43% |
| Monday | 62°F | Chance Rain Showers | 13 mph NE | 44% |
| Monday Night | 49°F | Chance Rain Showers | 6 to 10 mph NE | 44% |
| Tuesday | 61°F | Slight Chance Rain Showers then Partly Sunny | 8 mph ENE | 15% |
| Tuesday Night | 45°F | Partly Cloudy | 2 to 6 mph ENE | 2% |
| Wednesday | 66°F | Sunny | 5 mph ENE | 1% |
| Wednesday Night | 50°F | Partly Cloudy | 3 mph E | 5% |
| Thursday | 67°F | Partly Sunny | 3 mph ESE | 13% |
| Thursday Night | 53°F | Mostly Cloudy | 2 mph E | 10% |
| Friday | 69°F | Partly Sunny | 1 to 5 mph ESE | 6% |
| Friday Night | 54°F | Mostly Cloudy | 3 mph ESE | 9% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Union, IA
Last spring frost
Apr 27
First fall frost
Oct 10
Growing season
165 days
Hardiness zone
5a
Explore more for Union, IA: full frost dates · planting calendar · Iowa frost dates
Climate data from the nearest NOAA station, Eldora, Ia (9.8 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.