Union, LA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Union, a community in St. James County, Louisiana.
This Afternoon
84°F
Mostly Sunny
Mostly sunny. High near 84, with temperatures falling to around 76 in the afternoon. Southeast wind around 5 mph.
7-day forecast for Union
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 84°F | Mostly Sunny | 5 mph SE | 8% |
| Tonight | 67°F | Mostly Cloudy then Patchy Fog | 0 to 5 mph S | 14% |
| Wednesday | 80°F | Patchy Fog then Mostly Sunny | 0 to 5 mph NW | 16% |
| Wednesday Night | 56°F | Mostly Clear | 0 mph | 1% |
| Thursday | 81°F | Sunny | 0 mph | 10% |
| Thursday Night | 60°F | Chance Rain Showers | 0 mph | 29% |
| Friday | 79°F | Chance Rain Showers | 0 to 5 mph N | 32% |
| Friday Night | 54°F | Partly Cloudy | 0 to 5 mph N | 4% |
| Saturday | 76°F | Mostly Sunny | 5 mph N | 5% |
| Saturday Night | 49°F | Partly Cloudy | 0 to 5 mph N | 13% |
| Sunday | 70°F | Mostly Sunny | 5 mph N | 12% |
| Sunday Night | 45°F | Mostly Clear | 0 to 5 mph N | 5% |
| Monday | 72°F | Sunny | 0 to 5 mph NE | 3% |
| Monday Night | 45°F | Mostly Clear | 0 mph | 2% |
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 Nov 3, 2026.