Harman US

Union, IA Weather & Growing Conditions

Overnight
67°F
Chance Showers And Thunderstorms
A chance of showers and thunderstorms. Mostly cloudy, with a low around 67. South southeast wind around 6 mph. Chance of precipitation is 40%. New rainfall amounts between a quarter and half of an inch possible.

7-day forecast

WhenTempForecastWindPrecip
Overnight 67°F Chance Showers And Thunderstorms 6 mph SSE 41%
Saturday 79°F Showers And Thunderstorms Likely 8 mph WSW 57%
Saturday Night 60°F Chance Showers And Thunderstorms 9 mph N 33%
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%

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.