STATION:  YELLOWSTONE LAKE (KP60), WY

CLIMATOLOGICAL SUMMARY.  Period of Record: Aug 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        |  22.2  25.8  33.7  41.0  51.0  61.5  74.0  70.7  60.0  46.0  32.6  23.1 |   45.1
Avg Min Temp        |   1.4   0.4   8.1  17.0  26.6  33.3  40.2  37.3  30.5  22.7  12.3   4.0 |   19.5
Avg Temperature     |  11.8  13.1  20.9  29.0  38.8  47.4  57.1  54.0  45.2  34.3  22.5  13.5 |   32.3
                    |                                                                         |
Extremes:           |                                                                         |
    Extreme Max Temp|    42    66    60    65    78    82    86    86    79    69    57    41 |     86
                    |                                                                         |
    Date of Ext-Day |    20    08    09    29    28    29    31    01    05    01    06    01 |
               -Year|  2005  2000  2000  2007  2003  2007  2000  2000  1998  2001  1999  2003 |
                    |                                                                         |
    Extreme Min Temp|   -36   -38   -29   -17     8    23    27    25    13     0   -16   -34 |    -38
                    |                                                                         |
    Date of Ext-Day |    12    24    02    02    06    07    12    31    24    31    23    21 |
               -Year|  2007  2003  2002  2008  1999  2003  2008  2005  2000  2003  2003  1998 |
                    |                                                                         |
Heating Degree Days |  1649  1465  1365  1079   813   528   244   341   593   950  1276  1596 |  11900
Cooling Degree Days |     0     0     0     0     0     0     1     0     0     0     0     0 |      1
                    |                                                                         |
Avg Number of Days: |                                                                         |
    Max Temp >= 90  |   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
    Max Temp >= 75  |   0.0   0.0   0.0   0.0   0.2   2.6  14.8   9.4   1.4   0.0   0.0   0.0 |   28.4
    Max Temp <= 32  |  28.0  23.6  13.7   5.0   0.4   0.0   0.0   0.0   0.0   2.7  14.9  27.8 |  116.1
                    |                                                                         |
    Min Temp <= 32  |  31.0  28.1  31.0  29.9  27.8  13.8   1.0   5.3  20.7  30.5  29.5  31.0 |  279.6
    Min Temp <= 20  |  28.5  26.4  25.7  16.7   4.9   0.0   0.0   0.0   0.5   9.6  22.1  28.1 |  162.5
    Min Temp  <= 0  |  14.1  14.4   7.9   2.3   0.0   0.0   0.0   0.0   0.0   0.1   5.3  11.6 |   55.7
                    |                                                                         |
Avg Dew Point Temp  |   7.7   7.0  12.9  19.1  26.3  33.2  38.2  35.8  30.6  23.3  16.0   9.6 |   21.6
Avg Wet Bulb Temp   |  11.3  13.2  19.6  25.1  32.9  40.4  47.2  44.3  37.8  29.1  20.4  12.9 |   27.8
                    |                                                                         |
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                    |                                                                         |
Avg Sea Level Pres  | 30.27 30.21 30.12 30.05 30.06 30.04 30.09 30.10 30.11 30.16 30.22 30.25 |  30.14
(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   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0 |    0.0
    Heavy Fog       |   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
    Fog             |   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
    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     |  1.85  1.01  1.10  1.86  2.00  2.06  1.23  1.40  1.21  1.44  1.50  1.85 |  18.52
                    |                                                                         |
Maximum Daily       |  1.21  0.45  0.59  0.71  0.72  1.13  1.32  1.06  0.93  0.80  0.84  0.97 |   1.32
                    |                                                                         |
    Date of Ext-Day |    15    21    27    26    21    02    12    18    06    01    06    15 |
               -Year|  2008  2007  2007  2003  2008  2008  2007  2005  2002  2000  2001  2006 |
                    |                                                                         |
Avg Number of Days: |                                                                         |
    >= 0.01         |  14.5  12.5  12.4  13.1  14.1  12.9   9.4   9.7   9.1  11.9  11.7  14.8 |  146.2
    >= 0.10         |   5.9   3.7   4.0   5.6   6.9   5.9   4.0   3.9   3.9   4.3   5.0   6.1 |   59.3
    >= 0.25         |   1.9   0.6   1.0   2.3   3.0   2.8   1.6   1.9   1.5   1.9   1.6   2.3 |   22.5
    >= 0.50         |   0.5   0.0   0.3   0.7   0.6   0.9   0.3   0.7   0.4   0.5   0.5   0.6 |    6.0
    >= 1.00         |   0.2   0.0   0.0   0.0   0.0   0.1   0.1   0.1   0.0   0.0   0.0   0.0 |    0.5
                    |                                                                         |
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                    |                                                                         |
WIND (MPH)          |   Jan   Feb   Mar   Apr   May   Jun   Jul   Aug   Sep   Oct   Nov   Dec |   Year
                    |                                                                         |
Daily Avg Wind Speed|   2.2   2.6   3.5   3.4   3.6   3.9   3.5   3.7   3.5   3.2   3.1   2.8 |    3.3
Daily Avg Max 2-Min |   9.9  11.0  13.1  13.3  13.4  14.4  14.4  14.1  12.5  11.8  10.5  10.1 |   12.4
Daily Avg Peak Gust |  15.0  16.5  19.9  19.8  20.3  21.8  22.1  21.6  18.9  17.8  16.5  15.5 |   18.8
                    |                                                                         |
Maximum Daily Avg   |   9.6   9.2  10.8   8.6   8.1   7.8   7.9   7.2   8.3   9.3   9.2   9.4 |   10.8
                    |                                                                         |
Maximum 2-Minute Avg|    23    22    25    53    23    26    24    26    24    25    22    22 |     53
                    |                                                                         |
Date of Max 2min-Day|    16    02    06    28    18    01    22    21    16    28    13    17 |
               -Year|  1999  1999  2004  2005  2002  2001  2002  1998  2005  1999  2008  1998 |
                    |                                                                         |
Maximum Peak Gust   |    36    39    41    87    41    40    39    44    38    38    39    39 |     87
                    |                                                                         |
Date of Max Gust-Day|    28    02    16    28    20    01    06    09    10    30    13    15 |
               -Year|  2008  1999  1999  2005  2007  2001  2007  2007  2000  2003  2008  2006 |
                    |                                                                         |
Avg Number of Days: |                                                                         |
   Peak Gust >=30   |   1.2   0.6   2.3   1.5   1.7   2.5   2.6   3.0   1.1   1.4   1.4   1.2 |   20.4
   Peak Gust >=40   |   0.0   0.0   0.1   0.1   0.1   0.1   0.0   0.1   0.0   0.0   0.0   0.0 |    0.5
   Peak Gust >=50   |   0.0   0.0   0.0   0.1   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0 |    0.1
                    |                                                                         |
   Max 2-Minute >=30|   0.0   0.0   0.0   0.1   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0 |    0.1
   Max 2-Minute >=40|   0.0   0.0   0.0   0.1   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0 |    0.1
                    |                                                                         |
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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.