Climatological Report (Monthly)
Issued by NWS Denver/Boulder, CO

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CXUS55 KBOU 012101
CLMDEN

CLIMATE REPORT
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
303 PM MDT MON OCT 1 2018

...................................

...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF SEPTEMBER 2018...

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2018

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
                                          NORMAL
................................................................
TEMPERATURE (F)
RECORD
 HIGH              97   09/03/2017
                        09/06/2013
                        09/05/2013
 LOW               17   09/29/1985
HIGHEST            96   09/13        91       5       97  09/03
LOWEST             36   09/29        35       1       40  09/20
                        09/25
AVG. MAXIMUM     82.7              78.5     4.2     79.0
AVG. MINIMUM     52.8              48.3     4.5     51.3
MEAN             67.8              63.4     4.4     65.1
DAYS MAX >= 90      9               3.4     5.6        9
DAYS MAX <= 32      0               0.0     0.0        0
DAYS MIN <= 32      0               0.8    -0.8        0
DAYS MIN <= 0       0               0.0     0.0        0

PRECIPITATION (INCHES)
RECORD
 MAXIMUM         5.61   2013
 MINIMUM            T   1892
                        1944
TOTALS           0.18              0.96   -0.78     1.26
DAILY AVG.       0.01              0.03   -0.02     0.04
DAYS >= .01         5               6.5    -1.5        6
DAYS >= .10         0               3.3    -3.3        2
DAYS >= .50         0               0.6    -0.6        1
DAYS >= 1.00        0               0.1    -0.1        0
GREATEST
 24 HR. TOTAL    0.08   09/19

SNOWFALL (INCHES)
 TOTAL            0.0
RECORD
 TOTAL           17.2  1971         1.3

DEGREE_DAYS
HEATING TOTAL      69               125     -56      122
 SINCE 7/1         78               141     -63      130
COOLING TOTAL     160                76      84      131
 SINCE 1/1       1022               764     258      880

FREEZE DATES
RECORD
 EARLIEST     09/08/1962
 LATEST       06/08/2007
EARLIEST                        10/07
LATEST                          05/05
.................................................................

WIND (MPH)
AVERAGE WIND SPEED              9.7
RESULTANT WIND SPEED/DIRECTION   3/170
HIGHEST WIND SPEED/DIRECTION    37/270    DATE  09/19
HIGHEST GUST SPEED/DIRECTION    49/270    DATE  09/19

SKY COVER
AVERAGE SKY COVER           0.40
NUMBER OF DAYS FAIR           13
NUMBER OF DAYS PC             13
NUMBER OF DAYS CLOUDY          4

AVERAGE RH (PERCENT)     43

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORMS             5   MIXED PRECIP           0
HEAVY RAIN                0   MODERATE RAIN          0
LIGHT RAIN                9   FREEZING RAIN          0
LT FREEZING RAIN          0   HAIL                   0
HEAVY SNOW                0   SNOW                   0
LIGHT SNOW                0   FOG W/VIS <=1/4 MILE   3
FOG                       5   HAZE                   2

-  INDICATES NEGATIVE NUMBERS.
R  INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T  INDICATES TRACE AMOUNT.

...SEPTEMBER 2018 6TH WARMEST SINCE RECORDS BEGAN 1872...

IN SUMMARY, SEPTMEBER 2018 FINISHED WITH ABOVE AVERAGE TEMPERATURES
AND BELOW AVERAGE PRECIPITATION. MUCH OF THE MONTH WAS DOMINATED BY
A RIDGE OF HIGH PRESSURE WHICH HELD FIRM OVER THE SOUTHERN UNITED
STATES. THIS PROVIDED AN EXTENDED PERIOD OF WARM AND DRY SOUTHWEST
FLOW ALOFT OVER COLORADO. AS A RESULT, TEMPERATURES IN THE MIDDLE
PORTION OF THE MONTH WERE ABLE TO CONSISTENTLY REACH HIGH
TEMPERATURES IN THE 90S IN DENVER AND ACROSS THE EASTERN PLAINS WITH
MILD DAYTIME AND OVERNIGHT TEMPERATURES IN THE MOUNTAINS AS WELL.

TEMPERATURES:
THE AVERAGE TEMPERATURE AT DENVER INTERNATIONAL AIRPORT
FOR THE MONTH OF SEPTEMBER WAS 67.8 DEGREES F, WHICH IS 4.4 DEGREES
ABOVE THE NORMAL OF 63.4 DEGREES. THIS RANKS 6TH WARMEST SINCE
RECORDS BEGAN IN 1872. THE WARMEST SEPTEMBER ON RECORD OCCURRED,
OCCURRED RECENTLY IN 2015 WITH AN AVERAGE TEMPERATURE OF 69.4
DEGREES. THE COLDEST SEPTEMBER ON RECORD OCCURRED IN 1912 WITH A
MONTHLY AVERAGE OF 54.7 DEGREES. NUMEROUS HIGH TEMPERATURE RECORDS
WERE SET OR TIED IN THE SEPTEMBER 2018. A RECORD HIGH TEMPERATURE
WAS TIED ON 10TH WITH A HIGH OF 93, A RECORD HIGH WAS SET ON THE
11TH WITH A HIGH OF 93, A RECORD HIGH WAS TIED ON THE 13TH WITH A
HIGH OF 96 AND A RECORD HIGH WAS TIED ON THE 14TH WITH A HIGH OF 92.
IN ADDITION, A RECORD HIGH MINIMUM WAS SET ON THE 13TH WHEN THE
MORNING LOW ONLY FELL TO 64 DEGREES.

SINCE 1872
TEN WARMEST SEPTEMBER AVERAGE TEMPS IN DENVER WEATHER HISTORY:
69.4 2015
68.3 1948
68.2 1981, 1931
68.0 1998
67.8 2018
67.7 1933
67.6 1947
67.2 2005, 1994

ELEVEN COLDEST SEPTEMBER AVERAGE TEMPS IN DENVER WEATHER HISTORY:

54.7 1912
55.6 1965
56.3 1961
57.5 1971
58.1 1918
58.8 1985
58.9 2006, 1929
59.2 1999
59.3 2003, 1913


PRECIPITATION:
SEPTEMBER 2018 RECEIVED 0.18 INCHES OF PRECIPITATION
WHICH IS 0.78 INCHES BELOW THE MONTHLY AVERAGE OF 0.96 INCHES. THE
HIGHEST PRECIPITATION AMOUNT OF 0.08 INCHES WAS RECEIVED ON THE 19TH.

SINCE 1872
ELEVEN WETTEST SEPTEMBER TOTALS IN DENVER WEATHER HISTORY:

5.61 INCHES 2013
4.67 INCHES 1961
3.78 INCHES 1909
3.70 INCHES 1902
3.42 INCHES 1938
2.95 INCHES 2012
2.89 INCHES 1936, 1918, 1875
2.85 INCHES 1973, 1971

TEN DRIEST SEPTEMBER TOTALS IN DENVER WEATHER HISTORY SINCE:

TRACE INCHES 1944, 1892
0.01 INCHES 1992, 1956
0.02 INCHES 1921, 1879
0.05 INCHES 1893
0.06 INCHES 2010, 1920, 1882

SNOWFALL:
DENVER RECEIVED NO SNOWFALL IN SEPTEMBER 2018. NORMAL
SNOWFALL IN DENVER IS 1.3 INCHES, BASED ON THE 1981 THROUGH 2010
NCEI AVERAGES.

SINCE 1878
HIGHEST SNOW TOTALS FOR SEPTEMBER IN DENVER WEATHER HISTORY:

17.2 1971
16.5 1936
12.9 1959
11.4 1895
 8.7 1985
 7.4 1995
 6.5 1908
 5.8 1961
 5.5 1965
 5.4 1993

TEN LOWEST SNOW TOTALS FOR SEPTEMBER IN DENVER WEATHER HISTORY

ALL YEARS: NO SNOWFALL IN SEPTEMBER

THERE WERE 5 DAYS IN WHICH THUNDER WAS OBSERVED AT DENVER
INTERNATIONAL AIRPORT, 2 DAYS OF DENSE FOG WITH A VISIBILITY AT OR
BELOW 1/4 MILE AND 2 DAYS WITH SMOKE OR HAZE. A PEAK WIND GUST OF 49
MPH WAS RECORDED FROM THE WEST ON THE 19TH.

$$


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