STATION: HELENA REGIONAL AIRPORT (KHLN), MT
CLIMATOLOGICAL SUMMARY. Period of Record: Jul 1996 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
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Avg Max Temp | 33.0 38.4 47.8 56.8 67.0 74.4 87.7 85.1 73.0 58.4 43.3 33.5 | 58.2
Avg Min Temp | 13.5 18.4 24.8 31.7 41.2 48.8 55.5 52.5 43.6 33.3 22.9 14.9 | 33.4
Avg Temperature | 23.3 28.4 36.3 44.2 54.1 61.6 71.6 68.8 58.3 45.9 33.1 24.2 | 45.8
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Extremes: | |
Extreme Max Temp| 61 65 78 93 93 99 105 102 97 87 75 60 | 105
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Date of Ext-Day | 07 27 30 18 24 28 12 03 02 01 12 01 |
-Year| 2002 2006 2004 2001 2001 2007 2002 2001 2007 1997 1999 2008 |
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Extreme Min Temp| -33 -15 -12 3 23 30 39 38 19 4 -14 -27 | -33
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Date of Ext-Day | 12 17 08 02 08 10 16 19 23 31 28 26 |
-Year| 1997 2006 2002 2002 1997 1999 1999 1996 2000 1996 2006 1996 |
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Heating Degree Days | 1294 1033 891 623 350 149 15 30 229 593 956 1265 | 7428
Cooling Degree Days | 0 0 0 0 11 47 221 148 27 0 0 0 | 453
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Avg Number of Days: | |
Max Temp >= 90 | 0.0 0.0 0.0 0.1 0.7 2.3 14.1 10.6 1.9 0.0 0.0 0.0 | 29.7
Max Temp >= 75 | 0.0 0.0 0.1 1.7 8.4 14.8 29.2 27.5 14.5 2.1 0.2 0.0 | 98.4
Max Temp <= 32 | 12.4 7.0 2.9 0.7 0.0 0.0 0.0 0.0 0.0 0.5 5.7 12.6 | 41.9
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Min Temp <= 32 | 29.6 26.6 25.4 14.9 3.8 0.2 0.0 0.0 1.9 12.5 24.7 29.5 | 168.9
Min Temp <= 20 | 19.2 15.0 8.0 2.8 0.0 0.0 0.0 0.0 0.1 1.9 10.8 20.2 | 77.9
Min Temp <= 0 | 5.5 1.9 0.9 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.8 4.0 | 13.2
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Avg Dew Point Temp | 13.9 17.1 20.6 26.6 34.5 42.4 44.6 43.0 37.2 29.8 21.3 14.6 | 28.8
Avg Wet Bulb Temp | 20.3 24.3 30.0 36.5 44.6 51.2 56.5 54.4 47.3 38.5 28.5 21.1 | 37.8
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Avg Sea Level Pres | 30.19 30.17 30.10 30.05 30.00 29.97 29.97 29.99 30.03 30.11 30.18 30.23 | 30.08
(Inches of Mercury) | |
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WEATHER | Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec | Year
See disclaimer below| |
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Avg Number of Days: | |
Thunderstorms | 0.0 0.0 0.1 0.4 2.8 5.5 5.7 5.2 1.2 0.2 0.0 0.1 | 21.1
Heavy Fog | 3.4 1.4 1.2 0.8 0.5 0.3 0.2 0.2 0.2 0.5 1.3 3.3 | 13.3
Fog | 13.4 10.2 7.4 5.7 5.2 5.2 1.6 2.8 3.1 5.5 8.8 11.3 | 80.2
Hail | 0.0 0.0 0.0 0.0 0.1 0.0 0.2 0.2 0.0 0.0 0.0 0.1 | 0.5
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PRECIPITATION (In) | Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec | Year
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Average Monthly | 0.28 0.49 0.38 1.16 1.97 2.38 0.96 0.97 0.93 0.72 0.49 0.30 | 11.02
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Maximum Daily | 0.29 0.99 0.39 0.94 1.32 1.46 1.23 1.06 0.79 0.75 0.40 0.25 | 1.46
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Date of Ext-Day | 19 27 12 06 21 01 28 02 19 05 19 01 |
-Year| 1998 2006 2005 2006 2007 2005 1998 2004 2004 2007 2007 2005 |
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Avg Number of Days: | |
>= 0.01 | 6.1 7.0 6.4 8.7 10.8 12.8 6.7 7.1 5.7 6.5 6.3 5.9 | 89.9
>= 0.10 | 0.8 1.1 1.2 3.4 5.0 6.2 3.0 3.3 2.5 2.2 1.8 1.3 | 31.9
>= 0.25 | 0.1 0.3 0.3 1.3 2.8 2.9 1.2 1.1 1.4 0.7 0.5 0.1 | 12.7
>= 0.50 | 0.0 0.2 0.0 0.5 1.0 1.3 0.3 0.2 0.4 0.2 0.0 0.0 | 4.1
>= 1.00 | 0.0 0.0 0.0 0.0 0.2 0.3 0.1 0.1 0.0 0.0 0.0 0.0 | 0.7
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WIND (MPH) | Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec | Year
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Daily Avg Wind Speed| 5.9 6.3 7.8 8.1 8.1 7.9 7.0 6.4 6.4 6.4 5.8 6.0 | 6.8
Daily Avg Max 2-Min | 18.1 18.3 21.4 21.4 22.4 22.6 22.2 21.3 19.2 19.1 17.7 17.8 | 20.1
Daily Avg Peak Gust | 21.9 22.3 26.1 26.2 27.6 28.1 27.5 26.5 23.6 23.3 21.6 21.8 | 24.7
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Maximum Daily Avg | 18.8 23.0 21.1 20.8 19.3 18.9 16.1 15.8 20.5 21.2 21.7 21.3 | 23.0
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Maximum 2-Minute Avg| 46 51 47 41 44 52 52 46 52 51 43 43 | 52
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Date of Max 2min-Day| 30 02 28 20 26 24 14 24 25 31 18 27 |
-Year| 1997 1999 2001 1997 1998 1999 2002 1999 1999 1999 2003 1997 |
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Maximum Peak Gust | 59 64 58 49 61 60 58 59 64 61 56 62 | 64
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Date of Max Gust-Day| 30 02 06 20 20 24 13 24 25 31 17 31 |
-Year| 2004 1999 2004 1997 2008 1999 2001 1999 1999 1999 2003 2008 |
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Avg Number of Days: | |
Peak Gust >=30 | 8.7 7.1 10.9 9.2 12.0 12.6 12.1 10.8 7.6 8.2 7.6 9.1 | 115.9
Peak Gust >=40 | 2.2 2.4 3.1 1.9 2.1 3.1 2.5 3.2 1.4 1.7 2.1 2.3 | 28.0
Peak Gust >=50 | 0.5 0.6 0.3 0.0 0.4 0.7 0.3 0.4 0.3 0.3 0.4 0.5 | 4.7
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Max 2-Minute >=30| 3.1 3.3 5.2 3.2 4.3 4.0 4.0 4.2 2.6 3.0 3.4 0.0 | 40.3
Max 2-Minute >=40| 0.5 0.5 0.5 0.1 0.3 0.7 0.5 0.4 0.4 0.3 0.4 0.0 | 4.6
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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.