Union, MO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Union, a city in Franklin County, Missouri.
This Afternoon
97°F
Chance Showers And Thunderstorms
A chance of showers and thunderstorms. Sunny, with a high near 97. Heat index values as high as 104. Southwest wind around 1 mph. Chance of precipitation is 30%.
7-day forecast for Union
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 97°F | Chance Showers And Thunderstorms | 1 mph SW | 26% |
| Tonight | 70°F | Slight Chance Showers And Thunderstorms then Mostly Clear | 1 mph S | 21% |
| Saturday | 97°F | Partly Sunny | 1 to 5 mph SW | 4% |
| Saturday Night | 70°F | Partly Cloudy | 2 mph SW | 3% |
| Sunday | 93°F | Slight Chance Rain Showers then Slight Chance Showers And Thunderstorms | 3 mph W | 19% |
| Sunday Night | 64°F | Chance Showers And Thunderstorms then Showers And Thunderstorms Likely | 2 mph N | 67% |
| Monday | 79°F | Showers And Thunderstorms Likely | 1 to 5 mph N | 68% |
| Monday Night | 58°F | Showers And Thunderstorms Likely then Slight Chance Showers And Thunderstorms | 5 mph N | 67% |
| Tuesday | 71°F | Slight Chance Rain Showers then Mostly Cloudy | 6 mph N | 24% |
| Tuesday Night | 52°F | Mostly Cloudy | 1 to 5 mph N | 5% |
| Wednesday | 73°F | Mostly Sunny | 3 mph N | 1% |
| Wednesday Night | 52°F | Partly Cloudy | 2 mph N | 1% |
| Thursday | 74°F | Mostly Sunny | 0 to 3 mph N | 4% |
| Thursday Night | 55°F | Partly Cloudy | 2 mph NE | 3% |
Forecast source: National Weather Service (api.weather.gov) for Union (38.438, -90.996). Updated through the day.
Growing snapshot for Union
Last spring frost
Apr 11
First fall frost
Oct 23
Growing season
194 days
Hardiness zone
6b
More local growing data for Union: nearby ZIP 63084 weather · frost dates · planting calendar · Missouri frost dates
Nearby towns & communities
Berger
Charmwood
Gerald
Gray Summit
LaBarque Creek
Lake St. Clair
Lake Tekakwitha
Leslie
Miramiguoa Park
New Haven
Oak Grove Village
Pacific
Parkway
St. Clair
Stanton
Sullivan
Three Creeks
Villa Ridge
Washington
Climate data from the nearest NOAA station, Union, Mo (1.8 mi from Union). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.