Janesville, CA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Janesville, a community in Lassen County, California.
Tonight
48°F
Mostly Clear
Mostly clear, with a low around 48. West wind around 0 mph.
7-day forecast for Janesville
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 48°F | Mostly Clear | 0 mph | 0% |
| Sunday | 82°F | Partly Sunny | 0 to 10 mph E | 0% |
| Sunday Night | 51°F | Mostly Cloudy | 0 to 5 mph W | 0% |
| Monday | 85°F | Mostly Sunny | 0 to 5 mph NE | 0% |
| Monday Night | 50°F | Mostly Clear | 0 to 10 mph W | 0% |
| Tuesday | 87°F | Sunny | 0 to 5 mph N | 1% |
| Tuesday Night | 50°F | Mostly Clear | 5 mph W | 1% |
| Wednesday | 87°F | Sunny | 5 to 10 mph SW | 0% |
| Wednesday Night | 49°F | Partly Cloudy | 0 to 10 mph W | 0% |
| Thursday | 87°F | Sunny | 0 to 10 mph SW | 0% |
| Thursday Night | 49°F | Partly Cloudy | 0 to 10 mph SW | 0% |
| Friday | 82°F | Mostly Sunny | 0 to 15 mph SW | 1% |
| Friday Night | 47°F | Partly Cloudy | 0 to 15 mph SW | 2% |
| Saturday | 78°F | Mostly Sunny | 0 to 10 mph SW | 4% |
Forecast source: National Weather Service (api.weather.gov) for Janesville (40.301, -120.490). Updated through the day.
Growing snapshot for Janesville
Last spring frost
May 16
First fall frost
Oct 8
Growing season
143 days
Hardiness zone
7a
More local growing data for Janesville: nearby ZIP 96114 weather · frost dates · planting calendar · California frost dates
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Susanville
Climate data from the nearest NOAA station, Susanville 2Sw, Ca (12.6 mi from Janesville). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 20, 2026.