Altadena, CA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Altadena, a community in Los Angeles County, California.
This Afternoon
72°F
Mostly Sunny
Mostly sunny, with a high near 72. Southwest wind around 5 mph.
7-day forecast for Altadena
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 72°F | Mostly Sunny | 5 mph SW | 0% |
| Tonight | 52°F | Mostly Clear | 5 mph WNW | 0% |
| Wednesday | 72°F | Sunny | 5 mph NNW | 0% |
| Wednesday Night | 56°F | Partly Cloudy | 5 mph N | 0% |
| Thursday | 77°F | Sunny | 0 to 5 mph NW | 0% |
| Thursday Night | 57°F | Mostly Clear | 0 to 10 mph N | 0% |
| Friday | 80°F | Sunny | 0 to 10 mph NE | 0% |
| Friday Night | 59°F | Clear | 0 to 10 mph NNE | 0% |
| Saturday | 82°F | Sunny | 0 to 10 mph NW | 0% |
| Saturday Night | 62°F | Clear | 0 to 10 mph N | 0% |
| Sunday | 83°F | Sunny | 0 to 5 mph NW | 0% |
| Sunday Night | 63°F | Partly Cloudy | 0 to 5 mph N | 0% |
| Monday | 81°F | Mostly Sunny | 0 to 5 mph S | 0% |
| Monday Night | 62°F | Partly Cloudy | 0 to 5 mph NW | 1% |
Forecast source: National Weather Service (api.weather.gov) for Altadena (34.192, -118.136). Updated through the day.
Growing snapshot for Altadena
Last spring frost
Jan 8
First fall frost
Jan 7
Growing season
365 days
Hardiness zone
10b
More local growing data for Altadena: nearby ZIP 91001 weather · frost dates · planting calendar · California frost dates
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Climate data from the nearest NOAA station, Pasadena, Ca (3.2 mi from Altadena). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 3, 2026.