STATION:  WALLA WALLA REGIONAL ARPT (KALW), WA

CLIMATOLOGICAL SUMMARY.  Period of Record: Oct 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        |  41.9  47.2  55.8  62.3  70.6  78.9  90.5  88.1  77.6  63.3  49.1  41.0 |   63.8
Avg Min Temp        |  30.9  32.8  38.0  41.4  48.3  54.2  62.1  61.0  52.5  42.8  35.5  29.7 |   44.1
Avg Temperature     |  36.4  40.0  46.9  51.8  59.5  66.6  76.3  74.6  65.1  53.1  42.3  35.3 |   54.0
                    |                                                                         |
Extremes:           |                                                                         |
    Extreme Max Temp|    69    69    79    82    95   105   110   108    99    87    75    66 |    110
                    |                                                                         |
    Date of Ext-Day |    19    17    30    13    23    29    12    17    06    01    13    14 |
               -Year|  2005  2007  2003  2008  2001  2008  2002  2008  2003  2008  1999  2002 |
                    |                                                                         |
    Extreme Min Temp|   -12    11    25    27    32    41    46    46    33    15    14   -20 |    -20
                    |                                                                         |
    Date of Ext-Day |    05    18    02    01    07    06    11    31    23    31    28    10 |
               -Year|  2004  2006  2002  2008  2002  2005  2008  1999  2000  2002  2006  2000 |
                    |                                                                         |
Heating Degree Days |   887   706   562   395   203    62     3     5    78   374   682   921 |   4879
Cooling Degree Days |     0     0     0     0    32   109   349   301    78     4     0     0 |    874
                    |                                                                         |
Avg Number of Days: |                                                                         |
    Max Temp >= 90  |   0.0   0.0   0.0   0.0   1.3   4.7  18.1  15.0   2.2   0.0   0.0   0.0 |   41.3
    Max Temp >= 75  |   0.0   0.0   0.5   2.6  10.0  20.2  30.3  29.3  19.2   2.4   0.1   0.0 |  114.6
    Max Temp <= 32  |   5.9   0.9   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.1   1.6   7.6 |   16.2
                    |                                                                         |
    Min Temp <= 32  |  17.3  13.8   4.4   1.8   0.1   0.0   0.0   0.0   0.0   2.3  10.3  19.4 |   69.6
    Min Temp <= 20  |   2.8   0.6   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.3   1.0   3.9 |    8.6
    Min Temp  <= 0  |   0.3   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.3 |    0.6
                    |                                                                         |
Avg Dew Point Temp  |  29.9  31.2  33.8  36.8  42.2  45.3  45.1  45.1  41.2  38.4  34.6  29.5 |   37.7
Avg Wet Bulb Temp   |  33.4  36.0  41.0  44.7  50.6  55.1  58.9  58.1  52.5  45.8  38.8  32.9 |   45.7
                    |                                                                         |
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                    |                                                                         |
Avg Sea Level Pres  | 30.18 30.15 30.07 30.01 30.00 29.96 29.94 29.93 29.99 30.08 30.16 30.21 |  30.06
(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   |   0.2   0.2   0.1   0.7   1.6   1.6   1.2   1.6   0.4   0.5   0.1   1.2 |    9.4
    Heavy Fog       |   9.3   5.6   0.7   0.5   0.3   0.0   0.0   0.0   0.0   0.4   4.7   8.9 |   30.4
    Fog             |  18.3  11.3   6.9   4.9   4.6   3.1   0.1   0.8   1.6   4.2  13.1  18.0 |   86.9
    Hail            |   0.0   0.0   0.1   0.0   0.1   0.1   0.0   0.0   0.0   0.1   0.0   0.0 |    0.4
                    |                                                                         |
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                    |                                                                         |
PRECIPITATION (In)  |   Jan   Feb   Mar   Apr   May   Jun   Jul   Aug   Sep   Oct   Nov   Dec |   Year
                    |                                                                         |
Average Monthly     |  2.16  1.69  2.04  1.76  1.76  1.05  0.13  0.37  0.66  1.13  2.32  2.31 |  17.40
                    |                                                                         |
Maximum Daily       |  1.07  1.61  0.97  0.92  1.10  0.75  0.21  0.60  1.69  0.71  1.09  0.99 |   1.69
                    |                                                                         |
    Date of Ext-Day |    31    23    25    15    31    05    19    22    08    20    06    13 |
               -Year|  2003  2002  2006  2004  2000  2007  2007  2004  2003  2000  2006  2003 |
                    |                                                                         |
Avg Number of Days: |                                                                         |
    >= 0.01         |  14.0  11.0  11.7  10.4  10.4   6.0   2.4   2.8   4.0   7.6  12.9  14.8 |  108.0
    >= 0.10         |   6.5   5.4   6.1   4.9   4.7   3.2   0.4   1.3   1.9   3.4   6.7   7.2 |   51.6
    >= 0.25         |   2.9   1.8   3.2   2.9   2.5   1.5   0.0   0.4   0.8   1.5   3.4   3.2 |   24.1
    >= 0.50         |   0.9   0.5   1.1   0.7   0.7   0.6   0.0   0.2   0.2   0.6   0.8   0.7 |    7.0
    >= 1.00         |   0.1   0.1   0.0   0.0   0.1   0.0   0.0   0.0   0.1   0.0   0.2   0.0 |    0.6
                    |                                                                         |
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                    |                                                                         |
WIND (MPH)          |   Jan   Feb   Mar   Apr   May   Jun   Jul   Aug   Sep   Oct   Nov   Dec |   Year
                    |                                                                         |
Daily Avg Wind Speed|   7.4   7.6   9.4   8.6   8.5   8.6   8.4   8.1   7.4   7.1   7.3   7.5 |    8.0
Daily Avg Max 2-Min |  17.1  17.3  19.8  18.9  18.5  17.7  17.1  17.3  15.3  15.9  16.8  17.7 |   17.4
Daily Avg Peak Gust |  20.5  20.7  23.8  22.8  22.4  22.0  21.2  21.2  18.8  19.2  20.2  21.2 |   21.2
                    |                                                                         |
Maximum Daily Avg   |  23.5  23.5  22.4  19.1  18.6  16.4  17.7  16.4  20.5  20.5  26.1  28.4 |   28.4
                    |                                                                         |
Maximum 2-Minute Avg|    47    43    44    39    44    37    35    46    32    41    47    49 |     49
                    |                                                                         |
Date of Max 2min-Day|    30    05    02    27    08    21    22    02    25    28    12    16 |
               -Year|  2004  1999  1999  2004  2005  2008  2005  2004  1999  2003  2007  2002 |
                    |                                                                         |
Maximum Peak Gust   |    55    55    56    47    53    49    39    55    43    52    66    69 |     69
                    |                                                                         |
Date of Max Gust-Day|    30    05    02    27    19    21    22    02    25    28    12    16 |
               -Year|  2004  1999  1999  2004  2006  2008  2005  2004  1999  2003  2007  2002 |
                    |                                                                         |
Avg Number of Days: |                                                                         |
   Peak Gust >=30   |   7.2   6.4   8.1   5.0   4.7   3.2   2.4   2.5   1.5   3.4   6.8   8.3 |   59.5
   Peak Gust >=40   |   2.4   1.8   1.6   0.9   0.6   0.5   0.0   0.6   0.1   0.8   1.9   3.5 |   14.6
   Peak Gust >=50   |   0.3   0.5   0.3   0.0   0.2   0.0   0.0   0.1   0.0   0.1   0.4   0.8 |    2.7
                    |                                                                         |
   Max 2-Minute >=30|   4.3   2.7   3.6   2.3   1.3   0.6   0.3   0.9   0.4   1.0   2.8   0.0 |   20.2
   Max 2-Minute >=40|   0.5   0.6   0.2   0.0   0.3   0.0   0.0   0.1   0.0   0.1   0.4   0.0 |    2.2
                    |                                                                         |
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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.