Union, WA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Union, a community in Mason County, Washington.
Overnight
54°F
Clear
Clear. Low around 54, with temperatures rising to around 56 overnight. South wind around 1 mph.
7-day forecast for Union
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 54°F | Clear | 1 mph S | 0% |
| Tuesday | 83°F | Sunny then Areas Of Smoke | 0 to 7 mph ENE | 0% |
| Tuesday Night | 59°F | Areas Of Smoke | 0 to 6 mph NE | 0% |
| Wednesday | 87°F | Areas Of Smoke | 0 to 5 mph ENE | 0% |
| Wednesday Night | 60°F | Clear | 1 to 5 mph N | 0% |
| Thursday | 85°F | Sunny | 0 to 8 mph WSW | 0% |
| Thursday Night | 59°F | Mostly Clear | 3 to 8 mph WSW | 0% |
| Friday | 81°F | Sunny | 3 to 9 mph SW | 0% |
| Friday Night | 57°F | Mostly Clear | 0 to 9 mph WSW | 0% |
| Saturday | 77°F | Sunny | 0 to 10 mph SW | 0% |
| Saturday Night | 56°F | Mostly Clear | 0 to 10 mph WSW | 1% |
| Sunday | 72°F | Sunny | 0 to 10 mph SSW | 0% |
| Sunday Night | 55°F | Mostly Clear | 0 to 10 mph WSW | 0% |
| Monday | 72°F | Mostly Sunny | 0 to 8 mph SSW | 0% |
Forecast source: National Weather Service (api.weather.gov) for Union (47.348, -123.095). Updated through the day.
Growing snapshot for Union
Last spring frost
Mar 24
First fall frost
Nov 15
Growing season
235 days
Hardiness zone
8b
More local growing data for Union: nearby ZIP 98592 weather · frost dates · planting calendar · Washington frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Cushman Powerhouse #2, Wa (4.7 mi from Union). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.