STATION: GREAT FALLS INTERNATIONAL AIRPORT (KGTF), 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 | 35.4 39.1 45.5 54.8 65.2 72.2 86.1 83.4 70.9 57.7 43.8 35.9 | 57.5
Avg Min Temp | 15.5 18.1 22.3 30.1 38.7 46.2 52.6 50.9 43.1 33.1 24.9 16.8 | 32.7
Avg Temperature | 25.5 28.6 33.9 42.4 51.9 59.2 69.4 67.2 57.0 45.4 34.3 26.4 | 45.1
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Extremes: | |
Extreme Max Temp| 63 63 78 80 90 96 104 101 95 85 76 59 | 104
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Date of Ext-Day | 23 27 30 29 12 30 06 11 02 01 07 06 |
-Year| 2005 2006 2004 1998 2001 2008 2007 1996 1998 2008 1999 2003 |
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Extreme Min Temp| -31 -25 -22 -8 17 31 30 36 16 -9 -21 -27 | -31
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Date of Ext-Day | 12 17 08 21 02 10 26 17 23 31 28 26 |
-Year| 1997 2006 2002 2008 2005 1999 2003 2002 2000 2002 2006 1996 |
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Heating Degree Days | 1225 1029 964 677 410 198 32 54 266 608 921 1197 | 7581
Cooling Degree Days | 0 0 0 0 5 25 168 121 25 0 0 0 | 345
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Avg Number of Days: | |
Max Temp >= 90 | 0.0 0.0 0.0 0.0 0.2 1.2 11.5 8.9 1.4 0.0 0.0 0.0 | 23.1
Max Temp >= 75 | 0.0 0.0 0.1 1.4 6.9 11.8 28.4 25.5 11.9 2.4 0.1 0.0 | 88.5
Max Temp <= 32 | 9.6 7.4 5.0 1.4 0.1 0.0 0.0 0.0 0.1 1.2 6.2 9.4 | 40.4
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Min Temp <= 32 | 27.1 26.2 25.7 18.3 6.8 0.3 0.1 0.0 2.1 14.7 21.9 26.6 | 169.7
Min Temp <= 20 | 16.2 14.0 11.1 3.0 0.2 0.0 0.0 0.0 0.1 2.6 8.7 16.8 | 72.8
Min Temp <= 0 | 6.1 2.8 2.2 0.4 0.0 0.0 0.0 0.0 0.0 0.2 1.8 4.5 | 18.0
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Avg Dew Point Temp | 14.2 16.3 19.6 26.6 34.4 43.3 44.2 41.9 37.2 28.8 20.5 14.6 | 28.5
Avg Wet Bulb Temp | 21.9 24.3 28.5 35.6 43.8 50.8 55.7 53.7 46.9 38.0 29.0 22.6 | 37.6
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Avg Sea Level Pres | 30.12 30.11 30.08 30.05 29.98 29.93 29.92 29.95 29.98 30.07 30.11 30.14 | 30.04
(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 | 0.3 0.3 0.0 0.3 1.2 3.9 4.2 4.0 1.5 0.2 0.1 0.7 | 16.8
Heavy Fog | 1.4 2.3 3.2 1.9 0.8 0.3 0.0 0.1 0.7 2.2 1.9 2.2 | 16.9
Fog | 9.2 9.7 10.6 9.3 6.4 7.7 2.2 4.2 5.2 6.7 7.4 8.5 | 87.1
Hail | 0.0 0.0 0.0 0.0 0.4 0.4 0.3 0.4 0.2 0.0 0.0 0.1 | 1.8
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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 | 0.39 0.43 0.71 1.27 2.23 2.95 0.91 1.26 1.45 0.75 0.47 0.39 | 13.20
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Maximum Daily | 0.47 0.50 1.00 0.81 1.88 2.24 1.18 1.37 1.09 0.75 0.52 0.38 | 2.24
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Date of Ext-Day | 15 23 19 18 30 10 20 23 17 12 27 29 |
-Year| 2006 2007 2006 2007 1998 2002 1997 2004 1996 2000 2005 1996 |
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Avg Number of Days: | |
>= 0.01 | 5.8 6.5 7.4 10.0 10.7 13.0 5.9 7.4 7.6 6.3 5.4 5.3 | 91.3
>= 0.10 | 1.2 1.4 2.2 3.8 5.0 6.6 2.6 3.7 3.6 2.4 1.4 1.5 | 35.5
>= 0.25 | 0.2 0.3 0.8 1.8 2.8 3.3 1.0 1.5 2.2 0.8 0.6 0.4 | 15.6
>= 0.50 | 0.0 0.1 0.1 0.5 1.2 1.6 0.3 0.6 0.9 0.2 0.1 0.0 | 5.6
>= 1.00 | 0.0 0.0 0.1 0.0 0.4 0.4 0.2 0.1 0.1 0.0 0.0 0.0 | 1.2
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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| 13.7 12.1 12.0 10.9 10.8 9.8 9.1 9.0 10.1 11.7 13.2 13.9 | 11.4
Daily Avg Max 2-Min | 25.5 22.4 23.7 23.0 23.4 22.6 22.3 22.3 21.6 23.4 24.6 25.7 | 23.4
Daily Avg Peak Gust | 29.6 26.2 28.2 27.7 28.4 27.9 27.7 27.7 26.3 27.7 29.0 30.2 | 28.0
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Maximum Daily Avg | 30.2 31.1 29.8 26.3 26.3 21.5 19.1 22.4 25.6 26.5 29.7 27.9 | 31.1
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Maximum 2-Minute Avg| 51 54 49 52 48 52 43 51 49 54 58 55 | 58
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Date of Max 2min-Day| 12 11 07 13 29 04 28 16 09 31 19 16 |
-Year| 2002 2002 2004 2002 1998 2006 2001 2002 1998 1999 2003 1999 |
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Maximum Peak Gust | 64 66 63 58 53 64 59 83 57 62 72 67 | 83
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Date of Max Gust-Day| 16 11 18 13 29 04 14 08 09 31 19 16 |
-Year| 2000 2002 2004 2002 1998 2006 2002 2003 1998 1999 2003 1999 |
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Avg Number of Days: | |
Peak Gust >=30 | 15.2 11.2 13.3 12.2 13.3 12.1 11.2 11.8 10.0 13.1 14.1 16.5 | 154.2
Peak Gust >=40 | 5.7 2.7 4.9 2.2 3.1 2.8 3.3 4.1 2.8 3.9 5.1 6.8 | 47.2
Peak Gust >=50 | 1.6 0.5 1.0 0.6 0.4 0.5 0.5 0.5 0.1 0.4 0.9 1.1 | 8.0
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Max 2-Minute >=30| 10.4 6.0 8.5 5.6 5.8 4.7 5.2 6.2 5.1 7.6 9.5 0.0 | 74.7
Max 2-Minute >=40| 2.8 0.8 1.8 0.6 0.6 0.6 0.5 0.5 0.5 1.2 1.5 0.0 | 11.2
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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.