Byron, CA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Byron, a community in Contra Costa County, California.
This Afternoon
92°F
Sunny
Sunny, with a high near 92. West northwest wind around 7 mph.
7-day forecast for Byron
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 92°F | Sunny | 7 mph WNW | 0% |
| Tonight | 59°F | Partly Cloudy | 2 to 6 mph WSW | 0% |
| Sunday | 83°F | Partly Sunny | 6 mph W | 0% |
| Sunday Night | 59°F | Mostly Cloudy | 6 mph WSW | 0% |
| Monday | 86°F | Sunny | 8 mph W | 0% |
| Monday Night | 58°F | Mostly Clear | 2 to 8 mph WSW | 0% |
| Tuesday | 87°F | Sunny | 2 to 6 mph W | 0% |
| Tuesday Night | 59°F | Clear | 1 to 6 mph W | 0% |
| Wednesday | 94°F | Sunny | 3 mph WNW | 0% |
| Wednesday Night | 64°F | Mostly Clear | 2 mph NW | 0% |
| Thursday | 98°F | Sunny | 0 to 3 mph NW | 0% |
| Thursday Night | 64°F | Mostly Clear | 3 mph W | 0% |
| Friday | 91°F | Sunny | 2 to 8 mph WSW | 0% |
| Friday Night | 61°F | Mostly Clear | 3 to 8 mph WSW | 0% |
Forecast source: National Weather Service (api.weather.gov) for Byron (37.876, -121.642). Updated through the day.
Growing snapshot for Byron
Last spring frost
Jan 19
First fall frost
Dec 10
Growing season
330 days
Hardiness zone
9b
More local growing data for Byron: nearby ZIP 94505 weather · frost dates · planting calendar · California frost dates
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Climate data from the nearest NOAA station, Tracy Pumping Plt, Ca (5.3 mi from Byron). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 20, 2026.