TODAY JUN02
TEMPERATURE74
HUMIDITY52
PRESSURE29.99
WIND COND.230 4.7
  • 9563Tue
  • 9959Wed
  • 9354Thu
  • 8453Fri
  • 7850Sat
daynightWeather update from Santa Rosa, Santa Rosa Sonoma County Airport at
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St. Helena 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
January36°F60°F46°F6.0"
February39°F64°F50°F5.7"
March41°F67°F52°F4.6"
April43°F71°F55°F2.4"
May46°F77°F60°F1.1"
June50°F83°F64°F0.4"
July52°F85°F65°F0.0"
August52°F84°F64°F0.0"
September49°F85°F64°F0.2"
October46°F78°F59°F2.0"
November41°F67°F52°F3.2"
December36°F59°F46°F6.9"

Did you know?

  • The highest monthly average temperature in St. Helena for July is 65 degrees.
  • The lowest monthly average temperature in St. Helena for December is 46 degrees.
  • The most monthly precipitation in St. Helena occurs in December with 6.9 inches.
  • The air quality index in St. Helena is 30% better than the national average.
  • The pollution index in St. Helena is 56% worse than the national average.

Compare St. Helena, CA Weather To Other Cities

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      St. Helena 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.
      IndexSt. HelenaCaliforniaNational
      Air quality index355550
      Pollution index7,898,29018,106,7265,066,862

      St. Helena air quality information

      MeasurementTotal
      Days measured365
      Days with good air quality296
      Days with moderate air quality69
      Days w/ poor A.Q. for sensitive groups
      Days with unhealthy air quality

      St. Helena air quality information

      PollutantTotal
      Arsenic0.260%
      Benzene0.080%
      Carbon Tetrachloride0.005%
      Lead0.240%
      Mercury0.270%

      Average monthly St. Helena temperature with heat index

      St. Helena monthly precipitation with daily maximum

      St. Helena monthly snow depth with daily maximum

      St. Helena monthly wind speed information

      Nearby cities with good air quality

      City, StatePopulationAir Quality IndexNational Avg.
      Kenwood, CA1,2273530%
      Penngrove, CA2,9403530%
      Santa Rosa, CA173,1653530%
      Calistoga, CA5,2813530%
      Rohnert Park, CA41,9283530%
      St. Helena, CA5,9953530%

      Cities with similar population

      City, StatePopulationAir Quality IndexNational Avg.
      Brookville, OH5,993484%
      Deschutes River Woods, OR5,9933236%
      Erwin, TN5,9984510%
      Bowleys Quarters, MD5,998468%
      Ranchettes, WY6,0004020%
      St. Helena, CA5,9953530%
      Source: The St. Helena, 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.