Union, LA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Union, a community in St. James County, Louisiana.
Overnight
71°F
Clear
Clear, with a low around 71. Wind around 0 mph.
7-day forecast for Union
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 71°F | Clear | 0 mph | 0% |
| Saturday | 94°F | Sunny | 0 to 5 mph NE | 2% |
| Saturday Night | 73°F | Clear | 0 to 5 mph S | 2% |
| Sunday | 95°F | Sunny | 0 mph | 9% |
| Sunday Night | 74°F | Mostly Clear | 0 mph | 6% |
| Monday | 95°F | Sunny then Slight Chance Showers And Thunderstorms | 0 to 5 mph N | 20% |
| Monday Night | 74°F | Slight Chance Showers And Thunderstorms then Mostly Clear | 0 mph | 20% |
| Tuesday | 95°F | Sunny then Slight Chance Showers And Thunderstorms | 0 to 5 mph NE | 18% |
| Tuesday Night | 74°F | Slight Chance Showers And Thunderstorms then Mostly Clear | 0 mph | 18% |
| Wednesday | 94°F | Sunny | 0 to 5 mph NE | 7% |
| Wednesday Night | 73°F | Mostly Clear | 0 to 5 mph NE | 7% |
| Thursday | 92°F | Sunny | 5 mph NE | 6% |
| Thursday Night | 71°F | Mostly Clear | 0 to 5 mph NE | 6% |
| Friday | 91°F | Sunny | 5 mph NE | 3% |
Forecast source: National Weather Service (api.weather.gov) for Union (30.086, -90.889). Updated through the day.
Growing snapshot for Union
Last spring frost
Feb 21
First fall frost
Dec 5
Growing season
291 days
Hardiness zone
9a
More local growing data for Union: nearby ZIP 70086 weather · frost dates · planting calendar · Louisiana frost dates
Nearby towns & communities
Convent
Gramercy
Grand Point
Hester
Kraemer
Lutcher
Moonshine
North Vacherie
Paulina
Pleasure Bend
Romeville
South Vacherie
St. James
Welcome
Climate data from the nearest NOAA station, Donaldsonville 4 Sw, La (10 mi from Union). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.