STATION:  GREYBULL SOUTH BIG HORN COUNTY ARPT (KGEY), WY

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        |  30.7  37.5  51.3  61.2  70.8  81.6  93.7  89.4  75.5  60.4  45.8  31.6 |   60.8
Avg Min Temp        |   5.7  11.6  23.3  32.9  42.8  51.4  59.2  55.2  43.4  32.2  19.1   7.4 |   32.0
Avg Temperature     |  18.2  24.6  37.3  47.1  56.8  66.5  76.5  72.3  59.4  46.3  32.4  19.5 |   46.4
                    |                                                                         |
Extremes:           |                                                                         |
    Extreme Max Temp|    65    69    80    88    98   105   108   105    98    87    73    64 |    108
                    |                                                                         |
    Date of Ext-Day |    01    28    31    29    29    29    13    03    03    01    04    01 |
               -Year|  2003  2006  2004  2007  2003  2002  2002  2001  2007  2001  1999  1998 |
                    |                                                                         |
    Extreme Min Temp|   -33   -25   -12     5    20    36    44    36    27     9   -18   -21 |    -33
                    |                                                                         |
    Date of Ext-Day |    22    09    09    21    09    11    12    31    29    31    30    21 |
               -Year|  2008  2001  2002  2008  2002  2008  2008  2005  1999  2006  2006  1998 |
                    |                                                                         |
Heating Degree Days |  1452  1143   859   539   278    71     2    11   202   581   977  1409 |   7523
Cooling Degree Days |     0     0     0     1    24   116   358   238    35     0     0     0 |    772
                    |                                                                         |
Avg Number of Days: |                                                                         |
    Max Temp >= 90  |   0.0   0.0   0.0   0.0   1.3   6.4  24.7  17.7   3.6   0.0   0.0   0.0 |   53.8
    Max Temp >= 75  |   0.0   0.0   0.5   4.1  12.4  21.7  30.7  29.9  16.7   3.8   0.0   0.0 |  119.8
    Max Temp <= 32  |  17.3   8.9   2.5   0.2   0.0   0.0   0.0   0.0   0.0   0.6   5.2  15.1 |   49.7
                    |                                                                         |
    Min Temp <= 32  |  31.0  28.1  27.6  14.6   3.2   0.0   0.0   0.0   1.8  15.9  27.6  31.0 |  181.0
    Min Temp <= 20  |  28.9  21.6   9.4   1.5   0.1   0.0   0.0   0.0   0.0   1.5  14.3  27.5 |  104.8
    Min Temp  <= 0  |   9.1   5.2   0.8   0.0   0.0   0.0   0.0   0.0   0.0   0.0   2.2   8.1 |   25.5
                    |                                                                         |
Avg Dew Point Temp  |  11.0  14.1  20.4  26.0  34.4  41.3  45.1  42.3  36.1  29.0  19.3  11.5 |   27.5
Avg Wet Bulb Temp   |  15.7  20.8  30.5  38.1  46.0  53.1  58.7  55.6  47.6  37.9  27.0  16.7 |   37.3
                    |                                                                         |
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                    |                                                                         |
Avg Sea Level Pres  | 30.19 30.14 30.05 30.05 29.97 29.95 29.89 29.90 30.01 30.08 30.15 30.21 |  30.05
(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   0.2   0.9   2.1   3.9   4.5   4.1   1.9   0.0   0.0   0.0 |   17.7
    Heavy Fog       |   4.1   2.1   0.7   0.0   0.2   0.0   0.0   0.4   0.2   0.6   1.5   2.6 |   12.3
    Fog             |  11.3   8.5   7.1   3.7   3.3   2.5   0.4   1.2   3.1   4.1   5.0   8.5 |   58.7
    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     |  0.10  0.10  0.22  0.55  1.27  0.79  0.17  0.19  0.56  0.72  0.20  0.17 |   5.04
                    |                                                                         |
Maximum Daily       |  0.25  0.12  0.39  0.50  1.00  1.33  0.30  0.24  0.73  0.62  0.69  0.38 |   1.33
                    |                                                                         |
    Date of Ext-Day |    17    28    29    19    07    01    23    22    01    09    23    26 |
               -Year|  2008  2004  2006  2005  2005  2002  2004  2007  2008  2006  2002  2008 |
                    |                                                                         |
Avg Number of Days: |                                                                         |
    >= 0.01         |   2.0   2.6   3.5   5.3   7.6   6.2   2.9   3.8   4.8   5.5   3.2   2.6 |   50.0
    >= 0.10         |   0.2   0.3   0.5   1.6   3.7   2.2   0.6   0.7   1.8   2.1   0.4   0.5 |   14.6
    >= 0.25         |   0.1   0.0   0.2   0.8   1.8   0.9   0.1   0.0   0.8   1.2   0.1   0.1 |    6.1
    >= 0.50         |   0.0   0.0   0.0   0.1   0.6   0.2   0.0   0.0   0.2   0.4   0.1   0.0 |    1.6
    >= 1.00         |   0.0   0.0   0.0   0.0   0.1   0.1   0.0   0.0   0.0   0.0   0.0   0.0 |    0.2
                    |                                                                         |
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                    |                                                                         |
WIND (MPH)          |   Jan   Feb   Mar   Apr   May   Jun   Jul   Aug   Sep   Oct   Nov   Dec |   Year
                    |                                                                         |
Daily Avg Wind Speed|   4.2   5.7   7.7   8.9   8.9   8.1   7.1   6.8   6.7   6.3   5.3   5.0 |    6.7
Daily Avg Max 2-Min |  14.9  17.0  20.9  23.5  24.3  24.9  23.7  23.0  19.5  18.0  16.0  15.4 |   20.1
Daily Avg Peak Gust |  17.8  20.2  25.2  28.6  29.9  30.4  28.7  28.1  23.8  21.8  19.4  18.3 |   24.3
                    |                                                                         |
Maximum Daily Avg   |  20.4  22.2  32.7  23.8  28.5  21.4  19.7  17.7  23.2  25.9  24.9  27.6 |   32.7
                    |                                                                         |
Maximum 2-Minute Avg|    59    52    51    51    48    53    47    47    45    52    55    49 |     59
                    |                                                                         |
Date of Max 2min-Day|    28    13    28    23    21    07    07    21    19    29    11    13 |
               -Year|  2008  2008  2007  2002  2008  2007  2007  2002  2000  2003  2003  1999 |
                    |                                                                         |
Maximum Peak Gust   |    68    62    61    61    62    63    60    58    54    62    64    77 |     77
                    |                                                                         |
Date of Max Gust-Day|    28    13    28    23    10    07    07    05    19    29    11    26 |
               -Year|  2008  2008  2007  2002  2007  2007  2005  2007  2000  2003  2003  2008 |
                    |                                                                         |
Avg Number of Days: |                                                                         |
   Peak Gust >=30   |   4.9   6.3   9.4  12.7  16.0  14.7  13.1  13.5   8.0   7.5   5.5   5.5 |  117.1
   Peak Gust >=40   |   1.2   2.2   3.5   4.8   4.8   5.1   4.5   5.2   3.0   1.6   2.0   2.4 |   40.4
   Peak Gust >=50   |   0.3   0.5   0.6   0.5   1.1   1.2   1.0   0.7   0.3   0.3   0.5   0.6 |    7.7
                    |                                                                         |
   Max 2-Minute >=30|   2.3   3.6   5.6   7.2   8.1   8.1   7.0   7.4   4.8   3.6   3.2   0.0 |   61.0
   Max 2-Minute >=40|   0.4   0.7   1.1   1.2   1.3   1.8   1.3   0.9   0.5   0.6   0.5   0.0 |   10.4
                    |                                                                         |
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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.