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Key findings

  • The highest monthly average temperature in Grass Valley for July is 71 degrees
  • The lowest monthly average temperature in Grass Valley for December is 39 degrees
  • The most monthly precipitation in Grass Valley occurs in December with 11.7 inches
  • The air quality index in Grass Valley is 12% better than the national average
  • The pollution index in Grass Valley is 15% better than the national average

Compare Grass Valley, CA Weather

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      Grass Valley Average Temperature

      In the event that the weather data was unavailable for this city, estimates based upon nearby cities were used.
      MonthTemp. (min)Temp. (max)Temp. (avg)Precipitation
      January35°F49°F41°F7.8"
      February35°F47°F40°F8.4"
      March36°F49°F41°F10.1"
      April38°F54°F45°F5.7"
      May46°F62°F53°F3.7"
      June55°F71°F62°F1.4"
      July64°F79°F71°F0.1"
      August63°F79°F70°F0.1"
      September58°F74°F65°F1.4"
      October48°F63°F54°F4.8"
      November40°F53°F46°F7.3"
      December34°F46°F39°F11.7"

      Grass Valley air quality index & pollution index

      In the event that the air quality/pollution data was unavailable for this city, estimates based upon nearby cities were used.
      IndexGrass ValleyCaliforniaNational
      Air quality index445550
      Pollution index4,289,31018,106,7265,066,862

      Grass Valley air quality information

      MeasurementTotal
      Days measured365
      Days with good air quality239
      Days with moderate air quality124
      Days w/ poor A.Q. for sensitive groups2
      Days with unhealthy air quality0

      Grass Valley air quality information

      PollutantTotal
      Arsenic0.050%
      Benzene0.070%
      Carbon Tetrachloride0.001%
      Lead0.060%
      Mercury0.010%

      Average monthly Grass Valley temperature with heat index

      Grass Valley monthly precipitation with daily maximum

      Grass Valley monthly snow depth with daily maximum

      Grass Valley monthly wind speed information

      Nearby cities with good air quality

      City, StatePopulationAir Quality IndexNational Avg.
      Nevada City, CA3,1174412%
      North San Juan, CA2934412%
      Colfax, CA2,1894412%
      Alta, CA4484412%
      Penn Valley, CA1,6074412%
      Grass Valley, CA12,8614412%

      Cities with similar population

      City, StatePopulationAir Quality IndexNational Avg.
      Gaffney, SC12,8593628%
      Grenada, MS12,8633334%
      Luling, LA12,8554510%
      Herrin, IL12,8684314%
      Malibu, CA12,8537244%
      Grass Valley, CA12,8614412%
      Source: The Grass Valley, CA weather data displayed above is derived from the NOAA (National Oceanic and Atmospheric). Air quality and pollution data is derived from the EPA (United States Environmental Protection Agency). Air quality and pollution levels measured in a particular area may not be representative of the entire county.