Grass Valley, CA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Grass Valley, a city in Nevada County, California.
Tonight
40°F
Patchy Fog then Haze
Patchy fog before 10pm, then haze and patchy fog between 10pm and 1am. Partly cloudy, with a low around 40. East northeast wind 1 to 5 mph. New rainfall amounts less than a tenth of an inch possible.
7-day forecast for Grass Valley
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 40°F | Patchy Fog then Haze | 1 to 5 mph ENE | 7% |
| Wednesday | 62°F | Sunny | 1 to 6 mph NNW | 0% |
| Wednesday Night | 41°F | Patchy Fog then Partly Cloudy | 3 mph NE | 0% |
| Thursday | 66°F | Sunny | 1 to 5 mph N | 0% |
| Thursday Night | 42°F | Mostly Clear | 1 to 5 mph NNW | 0% |
| Friday | 69°F | Sunny | 0 to 6 mph N | 0% |
| Friday Night | 47°F | Mostly Clear | 0 to 5 mph NE | 0% |
| Saturday | 71°F | Sunny | 0 to 5 mph W | 0% |
| Saturday Night | 49°F | Mostly Clear | 0 to 5 mph ENE | 0% |
| Sunday | 71°F | Mostly Sunny | 0 to 5 mph W | 0% |
| Sunday Night | 49°F | Partly Cloudy | 2 mph NE | 0% |
| Monday | 68°F | Partly Sunny | 0 to 3 mph ESE | 4% |
| Monday Night | 47°F | Partly Cloudy | 2 mph NE | 4% |
| Tuesday | 68°F | Mostly Sunny | 2 mph SSE | 10% |
Forecast source: National Weather Service (api.weather.gov) for Grass Valley (39.220, -121.053). Updated through the day.
Growing snapshot for Grass Valley
Last spring frost
Apr 14
First fall frost
Nov 20
Growing season
218 days
Hardiness zone
9a
More local growing data for Grass Valley: nearby ZIP 95945 weather · frost dates · planting calendar · California frost dates
Nearby towns & communities
Alta Sierra
Floriston
Graniteville
Lake Wildwood
Nevada City
Penn Valley
Rough and Ready
Truckee
Washington
Climate data from the nearest NOAA station, Nevada City, Ca (3.9 mi from Grass Valley). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.