September Climate Outlook for Caribou

                 ...A STATISTICAL PREVIEW OF CARIBOU'S SEPTEMBER WEATHER...

Like most locations across the northern tier of the United States, temperatures begin a more rapid downward slope of daily temperatures during the month of September at caribou. 

The warmest temperature ever observed during the month of September was 92 degrees on September 1, 2010.  The coldest temperature ever observed in September was 23 degrees on September 29, 1980.

Frost is possible at any time during the month of September, although it becomes an increasingly likely event during the 2nd half of the month. The earliest occurrence of a temperature of 32 degrees or lower was observed on September 3, 1976.  The latest date for the first freezing temperature was September 30, 2001.  The average date (1981-2010 normals) of the first freezing temperature at caribou is September 20th. 

Although rare, snow has been observed during the month of September.  The earliest occurrence of a trace of snow was September 13, 1963.  A trace of snow has been observed a number of times during the second half of the month.  The earliest measurable snowfall was on September 29, 1991 when 2.1 inches of snow was observed. 

Tropical systems or the remains of tropical systems occasionally can affect the area with heavy rainfall and gusty wind.  September is the most likely time of the year for the area to be impacted by a tropical or ex-tropical system.

The frequency of thunderstorms drops off fairly rapidly in September, and the threat of severe thunderstorms drops off even more so. 

SEPTEMBER: CARIBOU’S TOP 5 WARMEST (AVERAGE TEMPERATURES):

61.7 DEGREES 1999

61.4 2015

61.0 2017

59.5 1961

58.6 2016

SEPTEMBER: CARIBOU’S TOP 5 COLDEST (AVERAGE TEMPERATURES):

50.2 DEGREES 1950

50.3 1956

50.3 1978

50.5 1986

50.8 1963

SEPTEMBER: CARIBOU’S TOP 5 WETTEST

8.81 INCHES 1999

8.14 1954

7.01 2013

6.80 1969

6.61 1967

SEPTEMBER: CARIBOU’S TOP 5 DRIEST

0.86 INCHES 1968

1.26 1950

1.33 1964

1.51 1992

1.54 1946

…SEPTEMBER STATISTICS…

….TEMPERATURES (1981-2010 NORMALS)

AVERAGE HIGH……………………….....................................65.4

AVERAGE LOW………...........................................................44.5

MONTHLY AVERAGE…………………………………………..55.0

…PRECIPITATION…

MONTHLY AVERAGE………………………………………….....3.32 INCHES

AVERAGE DAYS WITH MEASURABLE PRECIPITATION…..12 (11.8)

LARGEST CALENDAR DAY RAINFALL……………………….6.21 INCHES, 9/11/54 (2ND LARGEST ON RECORD)

AVERAGE SNOWFALL………………………………………….0.1 INCHES

…MISCELLANEOUS SEPTEMBER AVERAGES…

NORMAL HEATING DEGREE DAYS………………………..…313

NORMAL COOLING DEGREE DAYS……………………….…11

MEAN WIND SPEED……………………………………………..7.3 MPH

AVERAGE NUMBER OF DAYS W/THUNDERSTORMS….....1 (1.1)

AVERAGE NUMBER OF DAYS W/DENSE FOG…………..…2 (2.4)

MEAN NUMBER OF CLOUDY DAYS………………………….15

…SUNRISE AND SUNSET…

SEPTEMBER 1^ST…………………………………………………5:52 AM/7:11 PM

SEPTEMBER 30^TH……………………………………………….6:30 AM/6:13 PM

LOSS OF DAYLIGHT……………………………………………1 HOUR AND 36 MINUTES

The outlook from the Climate Prediction Center for September calls for an increased chance of above average temperatures.  There are currently no strong climate signals that would point toward an unusually wet or dry month.