STATION:  LEWISTOWN MUNICIPAL ARPT (KLWT), MT

CLIMATOLOGICAL SUMMARY.  Period of Record: Dec 2000 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        |  35.6  34.9  42.9  53.5  62.2  70.3  84.6  81.2  69.4  56.4  45.8  35.2 |   56.0
Avg Min Temp        |  14.0  13.5  20.8  28.8  37.4  45.3  52.7  49.8  41.4  31.3  22.6  13.6 |   31.0
Avg Temperature     |  24.8  24.2  31.9  41.2  49.8  57.8  68.7  65.5  55.4  43.9  34.2  24.4 |   43.5
                    |                                                                         |
Extremes:           |                                                                         |
    Extreme Max Temp|    68    63    76    82    88    94   101   100    94    83    73    61 |    101
                    |                                                                         |
    Date of Ext-Day |    07    11    30    28    12    30    13    10    02    01    04    19 |
               -Year|  2003  2005  2004  2001  2001  2003  2002  2003  2007  2001  2001  2004 |
                    |                                                                         |
    Extreme Min Temp|   -26   -30   -21     0    16    31    36    33    25    -8   -18   -29 |    -30
                    |                                                                         |
    Date of Ext-Day |    04    17    21    02    09    11    12    17    18    31    28    14 |
               -Year|  2004  2006  2002  2002  2002  2008  2008  2002  2003  2002  2006  2008 |
                    |                                                                         |
Heating Degree Days |  1248  1153  1027   715   473   232    34    78   305   654   924  1257 |   8100
Cooling Degree Days |     0     0     0     0     2    17   148    95    18     0     0     0 |    279
                    |                                                                         |
Avg Number of Days: |                                                                         |
    Max Temp >= 90  |   0.0   0.0   0.0   0.0   0.0   0.6   8.5   5.8   1.5   0.0   0.0   0.0 |   16.4
    Max Temp >= 75  |   0.0   0.0   0.1   1.5   4.9  10.9  28.2  23.2  10.3   2.8   0.0   0.0 |   82.0
    Max Temp <= 32  |   9.9  10.6   5.6   1.1   0.0   0.0   0.0   0.0   0.0   1.4   4.5  11.0 |   44.2
                    |                                                                         |
    Min Temp <= 32  |  28.7  27.6  27.2  20.5   9.4   0.1   0.0   0.0   2.3  15.9  23.8  29.7 |  185.2
    Min Temp <= 20  |  18.8  20.3  13.1   4.0   0.2   0.0   0.0   0.0   0.0   3.1  11.1  20.3 |   91.0
    Min Temp  <= 0  |   5.6   4.2   2.1   0.2   0.0   0.0   0.0   0.0   0.0   0.6   2.2   5.1 |   20.2
                    |                                                                         |
Avg Dew Point Temp  |  14.2  14.4  19.6  26.4  34.6  44.3  46.1  42.3  36.8  28.1  19.7  14.5 |   28.4
Avg Wet Bulb Temp   |  21.3  21.0  27.2  34.9  42.8  50.7  56.1  53.0  45.9  36.6  28.8  21.6 |   36.7
                    |                                                                         |
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                    |                                                                         |
Avg Sea Level Pres  | 30.12 30.10 30.07 30.03 29.99 29.94 29.93 29.96 29.99 30.07 30.11 30.12 |  30.03
(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   |   0.0   0.0   0.1   1.2   3.2   8.0   6.5   5.0   0.9   0.1   0.0   0.0 |   25.1
    Heavy Fog       |   1.4   3.1   3.2   1.8   1.6   0.2   0.1   0.4   0.6   1.4   1.1   2.4 |   17.4
    Fog             |   8.8  12.5  11.4   8.4   7.6   7.4   2.9   3.6   4.1   7.2   5.2   7.7 |   86.8
    Hail            |   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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                    |                                                                         |
PRECIPITATION (In)  |   Jan   Feb   Mar   Apr   May   Jun   Jul   Aug   Sep   Oct   Nov   Dec |   Year
                    |                                                                         |
Average Monthly     |  0.33  0.45  0.70  1.33  2.79  3.54  1.16  1.39  1.35  1.30  0.54  0.42 |  15.30
                    |                                                                         |
Maximum Daily       |  0.38  0.17  0.90  1.03  1.34  1.36  1.08  2.99  0.83  1.05  0.63  0.44 |   2.99
                    |                                                                         |
    Date of Ext-Day |    26    01    27    18    27    22    06    08    05    07    19    07 |
               -Year|  2002  2003  2007  2005  2006  2002  2007  2002  2001  2006  2007  2003 |
                    |                                                                         |
Avg Number of Days: |                                                                         |
    >= 0.01         |   6.2   8.2   8.8  11.5  12.6  14.6   9.8   8.6   8.9  10.1   6.0   6.0 |  111.4
    >= 0.10         |   0.8   1.1   2.4   3.2   6.4   8.1   3.2   3.6   4.2   3.8   1.6   1.1 |   39.6
    >= 0.25         |   0.2   0.0   0.4   1.8   3.8   4.8   1.5   1.4   1.6   1.6   0.5   0.3 |   17.8
    >= 0.50         |   0.0   0.0   0.1   0.5   1.6   2.4   0.4   0.4   0.8   0.2   0.2   0.0 |    6.6
    >= 1.00         |   0.0   0.0   0.0   0.1   0.6   0.5   0.1   0.1   0.0   0.1   0.0   0.0 |    1.6
                    |                                                                         |
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                    |                                                                         |
WIND (MPH)          |   Jan   Feb   Mar   Apr   May   Jun   Jul   Aug   Sep   Oct   Nov   Dec |   Year
                    |                                                                         |
Daily Avg Wind Speed|  10.9   9.4  10.3   9.5   9.6   8.7   7.7   7.9   8.1   9.3  10.7  10.6 |    9.4
Daily Avg Max 2-Min |  22.8  20.9  22.6  22.6  22.4  21.7  21.1  21.4  19.5  21.2  23.5  22.9 |   21.9
Daily Avg Peak Gust |  26.8  24.8  27.5  28.2  28.5  27.7  27.2  27.2  24.6  26.0  28.4  27.2 |   27.0
                    |                                                                         |
Maximum Daily Avg   |  25.4  25.0  25.3  19.7  24.2  20.8  16.0  16.3  19.5  22.1  26.1  26.3 |   26.3
                    |                                                                         |
Maximum 2-Minute Avg|    47    48    47    44    40    47    52    51    40    48    51    48 |     52
                    |                                                                         |
Date of Max 2min-Day|    30    16    24    27    16    04    16    16    01    29    19    13 |
               -Year|  2004  2007  2008  2001  2001  2006  2001  2002  2002  2003  2003  2006 |
                    |                                                                         |
Maximum Peak Gust   |    58    63    61    52    48    63    72    66    53    56    63    63 |     72
                    |                                                                         |
Date of Max Gust-Day|    06    16    24    23    16    04    14    01    01    29    12    13 |
               -Year|  2007  2007  2008  2002  2001  2006  2002  2007  2002  2003  2007  2006 |
                    |                                                                         |
Avg Number of Days: |                                                                         |
   Peak Gust >=30   |  11.9   8.7  12.1  11.6  14.4  13.3  11.1  10.9   7.8   9.9  12.9  12.9 |  137.5
   Peak Gust >=40   |   3.9   2.1   4.0   3.1   3.3   3.1   2.9   3.6   2.0   2.9   4.9   4.3 |   40.1
   Peak Gust >=50   |   0.8   0.5   0.9   0.4   0.0   0.5   0.8   0.4   0.1   0.4   1.2   1.0 |    6.9
                    |                                                                         |
   Max 2-Minute >=30|   6.0   4.6   6.7   4.3   4.4   5.0   4.2   4.8   2.0   4.4   8.2   0.0 |   54.7
   Max 2-Minute >=40|   1.0   0.6   0.9   0.4   0.1   0.5   0.8   0.5   0.1   0.4   1.8   0.0 |    7.0
                    |                                                                         |
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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.