STATION:  SANTA ROSA-SONOMA COUNTY AIRPORT (KSTS), CA

CLIMATOLOGICAL SUMMARY.  Period of Record: Jun 1998 to Dec 2008

Summaries based on unedited daily ASOS data.  Errors may be present.

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TEMPERATURE (F)     |   Jan   Feb   Mar   Apr   May   Jun   Jul   Aug   Sep   Oct   Nov   Dec |   Year
                    |                                                                         |
Avg Max Temp        |  56.5  60.2  65.4  67.8  75.7  81.6  83.8  84.2  82.3  76.0  64.2  56.9 |   71.2
Avg Min Temp        |  36.9  39.1  40.7  42.2  46.4  50.2  51.7  51.6  49.3  44.6  41.0  36.8 |   44.2
Avg Temperature     |  46.7  49.6  53.0  55.0  61.1  65.9  67.8  67.9  65.8  60.3  52.6  46.9 |   57.7
                    |                                                                         |
Extremes:           |                                                                         |
    Extreme Max Temp|    75    79    89    94   102   108   108   106   104   100    89    78 |    108
                    |                                                                         |
    Date of Ext-Day |    23    16    16    26    15    14    22    03    19    01    14    19 |
               -Year|  2006  2007  2004  2004  2008  2000  2006  1998  2000  2001  2008  1999 |
                    |                                                                         |
    Extreme Min Temp|    20    27    30    31    36    39    44    43    39    30    26    21 |     20
                    |                                                                         |
    Date of Ext-Day |    15    16    31    01    15    07    02    31    25    31    13    21 |
               -Year|  2007  2006  2008  1999  1999  1999  2003  2008  2005  2002  2000  1998 |
                    |                                                                         |
Heating Degree Days |   566   434   372   303   146    48    17    12    47   159   373   561 |   3040
Cooling Degree Days |     0     0     1     3    24    74   103   101    71    15     1     0 |    393
                    |                                                                         |
Avg Number of Days: |                                                                         |
    Max Temp >= 90  |   0.0   0.0   0.0   0.3   2.0   5.7   7.1   8.3   7.4   2.5   0.0   0.0 |   33.4
    Max Temp >= 75  |   0.1   0.4   4.9   5.6  16.1  23.4  27.4  27.6  23.7  17.4   2.8   0.2 |  149.6
    Max Temp <= 32  |   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0 |    0.0
                    |                                                                         |
    Min Temp <= 32  |   9.3   4.5   1.1   0.9   0.0   0.0   0.0   0.0   0.0   0.1   3.5  10.3 |   29.7
    Min Temp <= 20  |   0.1   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0 |    0.1
    Min Temp  <= 0  |   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0 |    0.0
                    |                                                                         |
Avg Dew Point Temp  |  41.0  42.0  42.8  43.4  47.1  49.5  52.9  52.5  49.8  45.3  44.9  40.8 |   46.0
Avg Wet Bulb Temp   |  43.6  45.5  47.5  48.6  52.6  56.1  57.8  57.6  55.3  51.3  48.2  43.5 |   50.6
                    |                                                                         |
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                    |                                                                         |
Avg Sea Level Pres  | 30.13 30.06 30.05 30.01 29.95 29.91 29.91 29.91 29.88 29.97 30.08 30.12 |  30.00
(Inches of Mercury) |                                                                         |
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                    |                                                                         |
WEATHER             |   Jan   Feb   Mar   Apr   May   Jun   Jul   Aug   Sep   Oct   Nov   Dec |   Year
See disclaimer below|                                                                         |
                    |                                                                         |
Avg Number of Days: |                                                                         |
    Thunderstorms   |   0.6   0.3   0.5   0.1   0.5   0.6   0.5   0.0   0.3   0.3   0.5   0.9 |    5.1
    Heavy Fog       |  16.2   9.9   8.1   5.8   4.4   2.4   3.3   5.5   5.4   7.8  12.0  12.5 |   93.3
    Fog             |  24.9  22.6  20.4  18.0  16.1  13.8  16.3  17.5  16.1  17.3  21.9  23.8 |  228.6
    Hail            |   0.1   0.0   0.0   0.1   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0 |    0.2
                    |                                                                         |
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                    |                                                                         |
PRECIPITATION (In)  |   Jan   Feb   Mar   Apr   May   Jun   Jul   Aug   Sep   Oct   Nov   Dec |   Year
                    |                                                                         |
Average Monthly     |  5.63  6.43  3.49  2.28  0.91  0.19  0.02  0.01  0.10  1.40  3.94  7.87 |  32.26
                    |                                                                         |
Maximum Daily       |  2.61  3.86  2.68  2.00  2.11  0.81  0.06  0.04  0.41  1.88  2.95  4.60 |   4.60
                    |                                                                         |
    Date of Ext-Day |    25    16    05    11    18    27    25    06    02    19    28    13 |
               -Year|  2008  2004  2006  2006  2005  2001  2003  1999  2000  2004  2001  2002 |
                    |                                                                         |
Avg Number of Days: |                                                                         |
    >= 0.01         |  20.3  17.7  13.0   9.7   4.4   1.5   0.6   0.6   2.8   7.9  16.3  18.2 |  113.0
    >= 0.10         |   9.6   9.2   6.3   4.8   1.8   0.4   0.0   0.0   0.2   2.3   6.2   9.2 |   49.9
    >= 0.25         |   6.4   6.9   4.5   3.2   1.0   0.3   0.0   0.0   0.1   1.5   3.8   7.3 |   35.0
    >= 0.50         |   4.0   4.2   2.1   1.6   0.4   0.1   0.0   0.0   0.0   0.9   2.8   5.0 |   21.2
    >= 1.00         |   1.7   2.1   0.8   0.4   0.2   0.0   0.0   0.0   0.0   0.5   1.2   2.7 |    9.6
                    |                                                                         |
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                    |                                                                         |
WIND (MPH)          |   Jan   Feb   Mar   Apr   May   Jun   Jul   Aug   Sep   Oct   Nov   Dec |   Year
                    |                                                                         |
Daily Avg Wind Speed|   3.5   4.5   5.1   5.4   5.8   5.9   5.4   5.0   4.4   4.0   3.4   3.8 |    4.7
Daily Avg Max 2-Min |  12.3  14.2  15.3  16.1  16.2  16.0  15.0  14.6  14.1  13.4  11.8  12.6 |   14.3
Daily Avg Peak Gust |  15.0  17.5  18.9  20.0  19.9  19.4  17.8  17.5  17.0  16.4  14.6  15.6 |   17.5
                    |                                                                         |
Maximum Daily Avg   |  15.4  15.3  13.6  16.6  15.5  14.0   7.7  10.4  11.5  15.7  13.1  16.5 |   16.6
                    |                                                                         |
Maximum 2-Minute Avg|    39    33    30    37    29    28    32    21    28    37    36    40 |     40
                    |                                                                         |
Date of Max 2min-Day|    06    09    04    03    25    08    06    30    29    22    20    16 |
               -Year|  2003  1999  2001  1999  2000  2002  2007  1999  2007  2000  2004  2002 |
                    |                                                                         |
Maximum Peak Gust   |    54    45    39    45    37    35    36    30    33    43    45    54 |     54
                    |                                                                         |
Date of Max Gust-Day|    04    09    04    03    20    03    18    30    19    22    07    31 |
               -Year|  2008  1999  2001  1999  2008  2008  2007  1999  2007  2000  2002  2002 |
                    |                                                                         |
Avg Number of Days: |                                                                         |
   Peak Gust >=30   |   1.7   2.6   1.8   1.4   1.7   1.0   0.2   0.3   0.4   1.1   1.1   3.4 |   16.7
   Peak Gust >=40   |   0.2   0.2   0.0   0.1   0.0   0.0   0.0   0.0   0.0   0.1   0.4   0.7 |    1.7
   Peak Gust >=50   |   0.1   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.2 |    0.3
                    |                                                                         |
   Max 2-Minute >=30|   0.2   0.3   0.1   0.1   0.0   0.0   0.1   0.0   0.0   0.1   0.4   0.0 |    1.3
   Max 2-Minute >=40|   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0 |    0.0
                    |                                                                         |
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Observations of WEATHER may me innacurate due to early ASOS inconsistancies.  Average days
with Thunderstorms may be low due to early mis-detection.

Heavy Fog = Visibility less than or equal to 1/4 mile.
Fog = Visibility greater than 1/4 mile or less than 7 miles.
Peak Gust = Maximum 5-second average.
Snowfall data not observed at ASOS stations.

Copyright ©2009 Western Regional Climate Center - Desert Research Institute - Reno, Nevada.