Harman US

Diablo, CA Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for Diablo, a community in Contra Costa County, California.

Today
88°F
Sunny
Sunny. High near 88, with temperatures falling to around 86 in the afternoon. Southwest wind 2 to 6 mph.

7-day forecast for Diablo

WhenTempForecastWindPrecip
Today 88°F Sunny 2 to 6 mph SW 0%
Tonight 55°F Partly Cloudy 5 mph S 0%
Sunday 78°F Mostly Cloudy 6 mph SW 3%
Sunday Night 54°F Mostly Cloudy 3 to 7 mph SW 3%
Monday 81°F Mostly Sunny 7 mph WSW 0%
Monday Night 54°F Mostly Clear 7 mph WSW 0%
Tuesday 84°F Sunny 6 mph WSW 0%
Tuesday Night 54°F Mostly Clear 0 to 6 mph SW 0%
Wednesday 95°F Sunny 0 to 3 mph W 0%
Wednesday Night 60°F Mostly Clear 0 to 3 mph SW 0%
Thursday 96°F Sunny 0 to 6 mph WSW 0%
Thursday Night 59°F Mostly Clear 1 to 6 mph WSW 0%
Friday 88°F Sunny 2 to 7 mph SW 0%
Friday Night 56°F Partly Cloudy 2 to 7 mph SW 0%

Forecast source: National Weather Service (api.weather.gov) for Diablo (37.841, -121.956). Updated through the day.

Growing snapshot for Diablo

Last spring frost
Mar 8
First fall frost
Dec 22
Growing season
282 days
Hardiness zone
9b

More local growing data for Diablo: nearby ZIP 94528 weather · frost dates · planting calendar · California frost dates

Nearby towns & communities

All California locations ›

Climate data from the nearest NOAA station, Mt Diablo Junction, Ca (3 mi from Diablo). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.