226  
CXUS55 KBOU 031927  
CLMDEN  
 
CLIMATE REPORT...UPDATED  
NATIONAL WEATHER SERVICE BOULDER, CO  
1224 PM MST TUE NOV 3 2009  
   
...............................  
 
   
..THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF OCTOBER 2009  
 
CLIMATE NORMAL PERIOD 1971 TO 2000  
CLIMATE RECORD PERIOD 1872 TO 2009  
 
WEATHER OBSERVED NORMAL DEPART LAST YEAR'S  
VALUE DATE(S) VALUE FROM VALUE DATE(S)  
NORMAL    
............................................................  
 
TEMPERATURE (F)  
RECORD  
HIGH 90 10/01/1892  
LOW -2 10/29/1917  
HIGHEST 84 10/18 90 -6 81 10/02  
10/01  
LOWEST 17 10/10 -2 19 23 10/27  
AVG. MAXIMUM 54.7 66.0 -11.3 66.2  
AVG. MINIMUM 31.1 35.9 -4.8 37.9  
MEAN 42.9 51.0 -8.1 52.1  
DAYS MAX >= 90 0 0.0 0.0 0  
DAYS MAX <= 32 3 0.3 2.7 0  
DAYS MIN <= 32 17 8.6 8.4 6  
DAYS MIN <= 0 0 0.0 0.0 0  
 
PRECIPITATION (INCHES)  
RECORD  
MAXIMUM 4.17 1969  
MINIMUM T 1934  
TOTALS 1.36 0.99 0.37 1.44  
DAILY AVG. 0.04 0.03 0.01 0.05  
DAYS >= .01 8 5.3 2.7 5  
DAYS >= .10 5 MM MM 3  
DAYS >= .50 0 MM MM 1  
DAYS >= 1.00 0 MM MM 1  
GREATEST  
24 HR. TOTAL 0.39 10/20 TO 10/21 1.06 10/05/08  
 
SNOWFALL (INCHES)  
RECORDS  
TOTAL 31.2 1969  
TOTALS 17.2 4.1  
 
DEGREE_DAYS  
HEATING TOTAL 676 436 240 393  
SINCE 7/1 815 582 233 537  
COOLING TOTAL 0 0 0 0  
SINCE 1/1 533 696 -163 825  
 
FREEZE DATES  
RECORD  
EARLIEST 09/08/1962  
LATEST 06/08/2007  
EARLIEST 10/02 10/07  
LATEST 05/05    
.............................................................  
 
WIND (MPH)  
AVERAGE WIND SPEED 9.6  
RESULTANT WIND SPEED/DIRECTION 1/293  
HIGHEST WIND SPEED/DIRECTION 37/350 DATE 10/29  
HIGHEST GUST SPEED/DIRECTION 54/200 DATE 10/05  
 
SKY COVER  
POSSIBLE SUNSHINE (PERCENT) MM  
 
NUMBER OF DAYS FAIR 4  
NUMBER OF DAYS PC 14  
NUMBER OF DAYS CLOUDY 13  
 
AVERAGE RH (PERCENT) 63  
 
WEATHER CONDITIONS. NUMBER OF DAYS WITH  
THUNDERSTORM 0 MIXED PRECIP 0  
HEAVY RAIN 0 RAIN 1  
LIGHT RAIN 7 FREEZING RAIN 0  
LT FREEZING RAIN 3 HAIL 0  
HEAVY SNOW 2 SNOW 4  
LIGHT SNOW 9 SLEET 0  
FOG 15 FOG W/VIS <= 1/4 MILE 9  
HAZE 6  
 
- INDICATES NEGATIVE NUMBERS.  
R INDICATES RECORD WAS SET OR TIED.  
MM INDICATES DATA IS MISSING.  
T INDICATES TRACE AMOUNT.  
 
 
 
...OCTOBER 2009 BECOMES DENVER'S SECOND COLDEST MONTH...  
...OCTOBER 2009 HAS MOVED INTO 5TH SNOWIEST OCTOBER...  
...NEW RECORD HIGH WIND GUST OF 54 MPH ON THE 5TH...  
 
IT WAS AN EVENTFUL OCTOBER AS COLD TEMPERATURES PREVAILED AND A STRONG LATE  
OCTOBER WINTER SNOW STORM THAT MOVED ACROSS DENVER.  
 
THERE WERE 5 LOW TEMPERATURE RECORDS EITHER TIED OR BROKEN AND 1 HIGH  
TEMPERATURE TIED. RECORD LOWS WERE ESTABLISHED ON OCTOBER 2ND...9TH AND 10TH.  
A TIED RECORD LOW WAS ESTABLISHED ON THE 3RD. A NEW RECORD LOW MAXIMUM WAS SET  
ON THE 26TH. ONLY ONE RECORD THAT DEALT WITH WARM TEMPERATURES WAS A TIED  
RECORD HIGH ON THE THE 18TH. THE MONTH'S TEMPERATURES RANGED FROM A  
THE TIED RECORD HIGH OF 84 DEGREES ON THE 18TH DOWN TO A LOW TEMPERATURE OF 17  
DEGREES...ALSO A RECORD ON THE 10TH. THE AVERAGE TEMPERATURE FOR THE 10TH WAS  
A VERY CHILLY 22 DEGREES. THE MONTH'S AVERAGE TEMPERATURE WAS ONLY 42.9  
DEGREES WHICH MOVED OCTOBER 2009 INTO THE 2ND COLDEST OCTOBER IN DENVER  
WEATHER HISTORY. THE COLDEST OCTOBER WAS A VERY FRIGID 39.0 DEGREES WHICH  
WAS RECORDED IN 1969. THERE WERE 17 DAYS WHEN THE LOW TEMPERATURES WERE 32  
DEGREES OR LOWER WHEREAS THE NORMAL AMOUNT IS ONLY 9. THREE HIGH TEMPERATURES  
DID NOT MAKE IT TO THE FREEZING MARK WHICH IS 3 ABOVE NORMAL.  
 
A STRONG WINTER STORM MOVED ACROSS THE DENVER METRO AREA WHICH INVOLVED  
3 DAYS...27TH THROUGH THE 29TH. 15.3 INCHES OF SNOW WAS OFFICIALLY MEASURED  
AT THE DENVER INTERNATIONAL AIRPORT (DIA). THIS STORM HELPED TO MOVE THE MONTH  
INTO 5TH SNOWIEST OCTOBER WITH A TOTAL OF 17.2 INCHES. THERE WERE NUMEROUS  
PLACES AROUND THE METRO AREA THAT MEASURED SNOW ABOVE 20 INCHES. IT HAS BEEN  
A LONG TIME SINCE DENVER HAS BEEN ABOVE NORMAL FOR SNOWFALL IN OCTOBER. THE  
17.2 INCHES WAS 11.0 INCHES ABOVE THE NORMAL OF 6.2 INCHES. THIS WINTER STORM  
ACCOUNTED FOR 0.69 INCH OF THE OCTOBER TOTAL MOISTURE WHICH WAS A RESPECTABLE  
1.39 INCHES. THIS WAS 0.37 INCH ABOVE THE NORMAL OF 0.99 INCH. IT WAS NOT  
ENOUGH LIQUID TO GET INTO THE TOP 10 WETTEST. EIGHT DAYS HAD MEASURABLE  
MOISTURE WITH 5 MEASURING 0.10 INCH OR MORE. NO RECORDS FOR PRECIPITATION WERE  
SET OR TIED DURING OCTOBER 2009.  
 
THERE WERE NO THUNDERSTORMS RECORDED AT DIA. EIGHT DAYS HAD DENSE FOG  
OBSERVED WHICH IS VISIBILITY OF 1/4 MILE OR LESS. THE NORMAL AMOUNT OF DENSE  
FOG AT DIA IS 1. THE PEAK WIND WAS 54 MPH FROM A SOUTHWEST DIRECTION ON THE  
5TH. THIS ESTABLISHED A NEW HIGH WIND GUST SURPASSING THE OLD RECORD OF 48  
MPH SET IN 1990.  
 
BENTON/JK  
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