
Grass Valley is a city in Nevada County, California, United States. The population was 14,922 at the 2006 census.
Grass Valley has warm to hot, dry summers, and wet, rainy winters. Summer is very dry but a thunderstorm may occur. The dry season is from May to September. November to mid-April is the true rainy season. Grass Valley has somewhat of an Oceanic climate, except that summers are warmer and dry enough to give Grass Valley characteristics of the Mediterranean Climate like much of Northern California. Snow does occur at times and can be heavy. The winter rains contribute to a heavy fuel-loading of brush and grass, which dry out during the summer, posing a wildfire hazard.