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
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| 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
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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.