Alum Rock, CA Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for Alum Rock, a community in Santa Clara County, California.

This Afternoon

80°F

Sunny

Sunny. High near 80, with temperatures falling to around 78 in the afternoon. Northwest wind around 10 mph, with gusts as high as 20 mph.

7-day forecast for Alum Rock

When	Temp	Forecast	Wind	Precip
This Afternoon	80°F	Sunny	10 mph NW	0%
Tonight	56°F	Mostly Clear then Patchy Fog	1 to 10 mph WNW	0%
Saturday	84°F	Patchy Fog then Sunny	1 to 9 mph WSW	0%
Saturday Night	58°F	Mostly Cloudy	1 to 7 mph WNW	0%
Sunday	79°F	Partly Sunny	1 to 7 mph W	1%
Sunday Night	56°F	Mostly Cloudy then Patchy Fog	2 to 7 mph W	1%
Monday	82°F	Patchy Fog then Mostly Sunny	2 to 7 mph WSW	0%
Monday Night	57°F	Mostly Clear	0 to 7 mph WSW	0%
Tuesday	85°F	Sunny	1 to 7 mph WSW	0%
Tuesday Night	60°F	Mostly Clear	0 to 7 mph WNW	0%
Wednesday	93°F	Sunny	0 to 7 mph NW	0%
Wednesday Night	64°F	Mostly Clear	0 to 7 mph NW	0%
Thursday	94°F	Sunny	0 to 8 mph WNW	0%
Thursday Night	63°F	Mostly Clear	1 to 8 mph WNW	0%

Forecast source: National Weather Service (api.weather.gov) for Alum Rock (37.369, -121.824). Updated through the day.

Growing snapshot for Alum Rock

Last spring frost

Jan 2

First fall frost

Dec 25

Growing season

362 days

Hardiness zone

More local growing data for Alum Rock: nearby ZIP 95116 weather · frost dates · planting calendar · California frost dates

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Climate data from the nearest NOAA station, San Jose, Ca (2.8 mi from Alum Rock). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.