Upper Marlboro 3 NNW Weather Records (USC00189070)
Record envelope, standing records and threshold days for Upper Marlboro 3 NNW (USC00189070), Maryland, United States, with 61 years of record.
Key Facts for Upper Marlboro 3 NNW
Upper Marlboro 3 NNW (USC00189070) is a weather station in Maryland, United States at 38.85 latitude and -76.77 longitude, 40 m (130 ft) above sea level.
The station reports from 1956 to 2016, 61 years of record.
1,464 records set at Upper Marlboro 3 NNW still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Upper Marlboro 3 NNW set a daily record low minimum temperature of -4.4 C (24.1 F) on 6 April 2016.
About the Station
Location: Maryland, United States, 38.85 latitude, -76.77 longitude.
Elevation: 40 m (130 ft).
Period of record: 1956 to 2016, 61 years.
Eligible elements: tmax, tmin, prcp, snow, snwd.
Daily Record Envelope and 2026
0 days at or beyond a record
Record highRecord low2026 daily maximum2026 daily minimum
The band shows the record high and record low for each calendar day at Upper Marlboro 3 NNW. The lines show the 2026 daily maximum and minimum. 0 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Upper Marlboro 3 NNW, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
23.9 C (75.0 F)
-24.4 C (-11.9 F)
n/a
n/a
Feb
26.7 C (80.1 F)
-22.2 C (-8.0 F)
n/a
n/a
Mar
31.7 C (89.1 F)
-16.7 C (1.9 F)
n/a
n/a
Apr
35.0 C (95.0 F)
-7.8 C (18.0 F)
n/a
n/a
May
36.1 C (97.0 F)
-2.2 C (28.0 F)
n/a
n/a
Jun
40.0 C (104.0 F)
3.9 C (39.0 F)
n/a
n/a
Jul
40.6 C (105.1 F)
6.1 C (43.0 F)
n/a
n/a
Aug
38.9 C (102.0 F)
3.9 C (39.0 F)
n/a
n/a
Sep
37.2 C (99.0 F)
-1.1 C (30.0 F)
n/a
n/a
Oct
33.9 C (93.0 F)
-6.7 C (19.9 F)
n/a
n/a
Nov
29.4 C (84.9 F)
-10.6 C (12.9 F)
n/a
n/a
Dec
26.7 C (80.1 F)
-17.2 C (1.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Upper Marlboro 3 NNW still stand. 1976 holds the most, with 43.
Standing records at Upper Marlboro 3 NNW by the year they were set
Year set
Standing records
1956
25
1957
35
1958
23
1959
31
1960
39
1961
33
1962
23
1963
38
1964
29
1965
30
1966
38
1967
40
1968
20
1969
14
1970
22
1971
28
1972
31
1973
21
1974
35
1975
18
1976
43
1977
18
1978
15
1979
42
1980
25
1981
18
1982
20
1983
16
1984
37
1985
21
1986
26
1987
23
1988
26
1989
15
1990
31
1991
28
1992
11
1993
12
1995
8
1996
24
1997
14
1998
23
1999
25
2000
32
2001
15
2002
38
2003
13
2004
17
2005
19
2006
21
2007
26
2008
11
2009
11
2010
32
2011
28
2012
35
2013
13
2014
24
2015
30
2016
5
All-Time Record Progression
6 new records
6 all-time records were set at Upper Marlboro 3 NNW between 2 September 2006 and 8 July 2012. Each dot is a new record.
When Upper Marlboro 3 NNW set new all-time records
Date
Kind
Detail
2006-09-02
Record daily precipitation
Record daily precipitation 127.0 mm (5.0 in)
2008-05-12
Record daily precipitation
Record daily precipitation 130.8 mm (5.1 in)
2011-08-28
Record daily precipitation
Record daily precipitation 133.9 mm (5.3 in)
2011-09-08
Record daily precipitation
Record daily precipitation 189.5 mm (7.5 in)
2012-06-30
Record high maximum temperature
Record high maximum temperature 40.0 C (104.0 F)
2012-07-08
Record high maximum temperature
Record high maximum temperature 40.6 C (105.1 F)
Wettest Day of Each Month
Sep: 189.5 mm (7.5 in)
The wettest day on record for each calendar month at Upper Marlboro 3 NNW. The most was 189.5 mm (7.5 in) on 8 September 2011.
Record daily precipitation for each month at Upper Marlboro 3 NNW
Month
Record daily precipitation (mm)
Date
Jan
57.2 mm (2.3 in)
1 January 1976
Feb
75.7 mm (3.0 in)
5 February 1998
Mar
54.4 mm (2.1 in)
29 March 1984
Apr
61.0 mm (2.4 in)
21 April 2008
May
130.8 mm (5.1 in)
12 May 2008
Jun
125.0 mm (4.9 in)
22 June 1972
Jul
102.9 mm (4.1 in)
14 July 1975
Aug
133.9 mm (5.3 in)
28 August 2011
Sep
189.5 mm (7.5 in)
8 September 2011
Oct
143.5 mm (5.6 in)
30 October 2012
Nov
68.1 mm (2.7 in)
7 November 1963
Dec
61.5 mm (2.4 in)
25 December 1986
Period of Record Coverage
1956 to 2016
Complete yearUnder 90 percent of days
60 years of record at Upper Marlboro 3 NNW, 1956 to 2016. 6 years have data for under 90 percent of days and are left out of rankings: 1956, 1989, 1992, 1993, 1995, 2016.
Cooler than the station meanWarmer than the station mean
One stripe for each of 51 complete years at Upper Marlboro 3 NNW, 1957 to 2015. Blue stripes are years cooler than the station's own mean of 12.6 C (54.8 F); red stripes are warmer. The coolest year was 1958, at 11.5 C (52.8 F), and the warmest was 2012, at 14.5 C (58.1 F). The strongest colour marks a difference of 1.9 C (3.4 F).
Annual mean temperature at Upper Marlboro 3 NNW as warming stripes, 1957 to 2015
Year
Annual mean temperature
Difference from the station mean
1957
12.9 C
+0.26 C
1958
11.5 C
-1.11 C
1959
13.0 C
+0.32 C
1960
11.7 C
-0.94 C
1961
12.0 C
-0.63 C
1962
11.7 C
-0.98 C
1963
11.6 C
-1.02 C
1964
12.4 C
-0.21 C
1965
12.2 C
-0.49 C
1966
11.7 C
-0.90 C
1967
11.6 C
-1.06 C
1968
12.5 C
-0.15 C
1969
12.3 C
-0.32 C
1970
12.6 C
-0.07 C
1971
12.7 C
+0.04 C
1972
12.1 C
-0.51 C
1973
13.2 C
+0.60 C
1974
12.4 C
-0.20 C
1975
12.7 C
+0.02 C
1976
11.6 C
-1.08 C
1977
12.5 C
-0.12 C
1978
11.8 C
-0.87 C
1979
12.0 C
-0.65 C
1980
12.4 C
-0.24 C
1982
12.4 C
-0.23 C
1983
12.6 C
-0.09 C
1984
12.6 C
0.00 C
1985
12.8 C
+0.11 C
1986
12.3 C
-0.35 C
1987
12.9 C
+0.30 C
1988
12.0 C
-0.68 C
1990
13.0 C
+0.31 C
1991
13.7 C
+1.03 C
1996
12.1 C
-0.59 C
1997
12.5 C
-0.17 C
1998
14.3 C
+1.61 C
2000
12.6 C
-0.06 C
2001
13.1 C
+0.41 C
2002
13.7 C
+1.09 C
2003
12.4 C
-0.26 C
2004
13.2 C
+0.53 C
2005
13.1 C
+0.50 C
2007
13.6 C
+0.98 C
2008
13.2 C
+0.59 C
2009
12.8 C
+0.14 C
2010
13.7 C
+1.03 C
2011
14.0 C
+1.40 C
2012
14.5 C
+1.87 C
2013
13.1 C
+0.45 C
2014
12.3 C
-0.33 C
2015
13.4 C
+0.75 C
The annual mean temperature here has risen by 0.3 C (0.2 to 0.3) per decade over 1957 to 2015. In Fahrenheit: 0.5 F (0.3 to 0.6) per decade. The slope is a straight line fitted to 51 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Upper Marlboro 3 NNW
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.3 C (0.2 to 0.3) per decade
0.5 F (0.3 to 0.6) per decade
1957 to 2015
51
Rise
Mean daily maximum
0.2 C (0.1 to 0.3) per decade
0.3 F (0.1 to 0.5) per decade
1957 to 2015
51
Rise
Mean daily minimum
0.3 C (0.2 to 0.4) per decade
0.6 F (0.4 to 0.8) per decade
1957 to 2015
51
Rise
A year is complete when all 12 months have at least 20 days of both daily maximum and daily minimum readings. The annual mean is the mean of the monthly means. The trend describes this one station over this period; it does not say what caused the change.
Extremes by Year
1956 to 2016
Yearly extremes at Upper Marlboro 3 NNW: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
40.6 C (105.1 F)
2012
35.9 C (96.5 F)
60
Coldest night (TNn)
-24.4 C (-11.9 F)
1984
-15.6 C (3.9 F)
60
Wettest day (Rx1day)
189.5 mm (7.5 in)
2011
65.8 mm (2.6 in)
60
Wettest five days (Rx5day)
291.4 mm (11.5 in)
1975
104.3 mm (4.1 in)
60
Longest dry spell (CDD)
38 days
2001
18 days
60
Hottest day (TXx)
The hottest day of the year at Upper Marlboro 3 NNW, 1956 to 2016. The record is 40.6 C (105.1 F) in 2012, marked on the chart; the median year is 35.9 C (96.5 F).
Hottest day (TXx) at Upper Marlboro 3 NNW by year
Year
Hottest day (TXx)
1956
36.7 C (98.1 F)
1957
37.8 C (100.0 F)
1958
34.4 C (93.9 F)
1959
37.2 C (99.0 F)
1960
34.4 C (93.9 F)
1961
34.4 C (93.9 F)
1962
36.1 C (97.0 F)
1963
36.1 C (97.0 F)
1964
35.6 C (96.1 F)
1965
35.0 C (95.0 F)
1966
37.8 C (100.0 F)
1967
35.0 C (95.0 F)
1968
35.0 C (95.0 F)
1969
37.2 C (99.0 F)
1970
35.0 C (95.0 F)
1971
34.4 C (93.9 F)
1972
35.0 C (95.0 F)
1973
36.1 C (97.0 F)
1974
35.6 C (96.1 F)
1975
35.6 C (96.1 F)
1976
33.9 C (93.0 F)
1977
36.7 C (98.1 F)
1978
36.1 C (97.0 F)
1979
33.9 C (93.0 F)
1980
37.8 C (100.0 F)
1981
35.6 C (96.1 F)
1982
35.0 C (95.0 F)
1983
38.9 C (102.0 F)
1984
35.0 C (95.0 F)
1985
36.7 C (98.1 F)
1986
36.7 C (98.1 F)
1987
38.3 C (100.9 F)
1988
38.9 C (102.0 F)
1989
35.6 C (96.1 F)
1990
36.1 C (97.0 F)
1991
38.9 C (102.0 F)
1992
35.0 C (95.0 F)
1993
35.6 C (96.1 F)
1995
36.7 C (98.1 F)
1996
34.4 C (93.9 F)
1997
37.8 C (100.0 F)
1998
36.7 C (98.1 F)
1999
37.8 C (100.0 F)
2000
34.4 C (93.9 F)
2001
35.6 C (96.1 F)
2002
38.3 C (100.9 F)
2003
34.4 C (93.9 F)
2004
33.3 C (91.9 F)
2005
37.2 C (99.0 F)
2006
37.2 C (99.0 F)
2007
37.8 C (100.0 F)
2008
36.1 C (97.0 F)
2009
35.6 C (96.1 F)
2010
38.9 C (102.0 F)
2011
38.9 C (102.0 F)
2012
40.6 C (105.1 F)
2013
35.0 C (95.0 F)
2014
35.6 C (96.1 F)
2015
35.6 C (96.1 F)
2016
33.3 C (91.9 F)
Coldest night (TNn)
The coldest night of the year at Upper Marlboro 3 NNW, 1956 to 2016. The record is -24.4 C (-11.9 F) in 1984, marked on the chart; the median year is -15.6 C (3.9 F).
Coldest night (TNn) at Upper Marlboro 3 NNW by year
Year
Coldest night (TNn)
1956
-10.0 C (14.0 F)
1957
-18.9 C (-2.0 F)
1958
-17.2 C (1.0 F)
1959
-16.1 C (3.0 F)
1960
-17.2 C (1.0 F)
1961
-23.9 C (-11.0 F)
1962
-16.7 C (1.9 F)
1963
-20.6 C (-5.1 F)
1964
-21.1 C (-6.0 F)
1965
-19.4 C (-2.9 F)
1966
-15.0 C (5.0 F)
1967
-20.0 C (-4.0 F)
1968
-20.6 C (-5.1 F)
1969
-13.3 C (8.1 F)
1970
-20.6 C (-5.1 F)
1971
-13.9 C (7.0 F)
1972
-16.7 C (1.9 F)
1973
-13.3 C (8.1 F)
1974
-15.6 C (3.9 F)
1975
-13.3 C (8.1 F)
1976
-17.2 C (1.0 F)
1977
-18.9 C (-2.0 F)
1978
-13.9 C (7.0 F)
1979
-22.2 C (-8.0 F)
1980
-16.7 C (1.9 F)
1981
-21.7 C (-7.1 F)
1982
-20.6 C (-5.1 F)
1983
-18.9 C (-2.0 F)
1984
-24.4 C (-11.9 F)
1985
-22.2 C (-8.0 F)
1986
-15.0 C (5.0 F)
1987
-23.3 C (-9.9 F)
1988
-20.0 C (-4.0 F)
1989
-12.2 C (10.0 F)
1990
-12.8 C (9.0 F)
1991
-15.0 C (5.0 F)
1992
-14.4 C (6.1 F)
1993
-13.3 C (8.1 F)
1995
-10.6 C (12.9 F)
1996
-22.2 C (-8.0 F)
1997
-16.1 C (3.0 F)
1998
-10.0 C (14.0 F)
1999
-14.4 C (6.1 F)
2000
-14.4 C (6.1 F)
2001
-11.1 C (12.0 F)
2002
-15.0 C (5.0 F)
2003
-15.6 C (3.9 F)
2004
-14.4 C (6.1 F)
2005
-15.6 C (3.9 F)
2006
-10.6 C (12.9 F)
2007
-12.8 C (9.0 F)
2008
-11.7 C (10.9 F)
2009
-17.8 C (0.0 F)
2010
-12.2 C (10.0 F)
2011
-13.9 C (7.0 F)
2012
-10.0 C (14.0 F)
2013
-12.2 C (10.0 F)
2014
-17.2 C (1.0 F)
2015
-17.8 C (0.0 F)
2016
-13.3 C (8.1 F)
Wettest day (Rx1day)
The wettest day of the year at Upper Marlboro 3 NNW, 1956 to 2016. The record is 189.5 mm (7.5 in) in 2011, marked on the chart; the median year is 65.8 mm (2.6 in).
Wettest day (Rx1day) at Upper Marlboro 3 NNW by year
Year
Wettest day (Rx1day)
1956
52.6 mm (2.1 in)
1957
44.5 mm (1.8 in)
1958
92.7 mm (3.6 in)
1959
78.2 mm (3.1 in)
1960
95.3 mm (3.8 in)
1961
47.5 mm (1.9 in)
1962
46.2 mm (1.8 in)
1963
68.1 mm (2.7 in)
1964
55.9 mm (2.2 in)
1965
45.0 mm (1.8 in)
1966
78.7 mm (3.1 in)
1967
39.4 mm (1.6 in)
1968
78.5 mm (3.1 in)
1969
56.1 mm (2.2 in)
1970
52.1 mm (2.1 in)
1971
102.9 mm (4.1 in)
1972
125.0 mm (4.9 in)
1973
96.5 mm (3.8 in)
1974
47.0 mm (1.9 in)
1975
125.7 mm (4.9 in)
1976
57.2 mm (2.3 in)
1977
59.4 mm (2.3 in)
1978
63.5 mm (2.5 in)
1979
111.5 mm (4.4 in)
1980
31.5 mm (1.2 in)
1981
63.5 mm (2.5 in)
1982
97.5 mm (3.8 in)
1983
55.9 mm (2.2 in)
1984
54.4 mm (2.1 in)
1985
124.7 mm (4.9 in)
1986
61.5 mm (2.4 in)
1987
46.0 mm (1.8 in)
1988
43.9 mm (1.7 in)
1989
70.4 mm (2.8 in)
1990
70.6 mm (2.8 in)
1991
45.2 mm (1.8 in)
1992
45.7 mm (1.8 in)
1993
45.7 mm (1.8 in)
1995
43.2 mm (1.7 in)
1996
57.7 mm (2.3 in)
1997
77.5 mm (3.1 in)
1998
75.7 mm (3.0 in)
1999
104.1 mm (4.1 in)
2000
75.9 mm (3.0 in)
2001
48.3 mm (1.9 in)
2002
52.8 mm (2.1 in)
2003
49.8 mm (2.0 in)
2004
75.2 mm (3.0 in)
2005
81.0 mm (3.2 in)
2006
127.0 mm (5.0 in)
2007
73.4 mm (2.9 in)
2008
130.8 mm (5.1 in)
2009
62.2 mm (2.4 in)
2010
84.6 mm (3.3 in)
2011
189.5 mm (7.5 in)
2012
143.5 mm (5.6 in)
2013
97.0 mm (3.8 in)
2014
87.6 mm (3.4 in)
2015
68.8 mm (2.7 in)
2016
37.1 mm (1.5 in)
Wettest five days (Rx5day)
The wettest five days of the year at Upper Marlboro 3 NNW, 1956 to 2016. The record is 291.4 mm (11.5 in) in 1975, marked on the chart; the median year is 104.3 mm (4.1 in).
Wettest five days (Rx5day) at Upper Marlboro 3 NNW by year
Year
Wettest five days (Rx5day)
1956
93.7 mm (3.7 in)
1957
79.5 mm (3.1 in)
1958
136.0 mm (5.4 in)
1959
80.7 mm (3.2 in)
1960
147.6 mm (5.8 in)
1961
74.9 mm (2.9 in)
1962
58.4 mm (2.3 in)
1963
112.3 mm (4.4 in)
1964
77.7 mm (3.1 in)
1965
56.8 mm (2.2 in)
1966
98.3 mm (3.9 in)
1967
114.9 mm (4.5 in)
1968
92.2 mm (3.6 in)
1969
117.3 mm (4.6 in)
1970
74.2 mm (2.9 in)
1971
141.8 mm (5.6 in)
1972
188.8 mm (7.4 in)
1973
104.4 mm (4.1 in)
1974
80.2 mm (3.2 in)
1975
291.4 mm (11.5 in)
1976
104.6 mm (4.1 in)
1977
105.3 mm (4.1 in)
1978
116.6 mm (4.6 in)
1979
114.5 mm (4.5 in)
1980
63.6 mm (2.5 in)
1981
101.4 mm (4.0 in)
1982
142.2 mm (5.6 in)
1983
117.6 mm (4.6 in)
1984
88.1 mm (3.5 in)
1985
135.7 mm (5.3 in)
1986
69.9 mm (2.8 in)
1987
65.1 mm (2.6 in)
1988
59.7 mm (2.4 in)
1989
111.5 mm (4.4 in)
1990
124.4 mm (4.9 in)
1991
69.5 mm (2.7 in)
1992
83.6 mm (3.3 in)
1993
70.1 mm (2.8 in)
1995
73.2 mm (2.9 in)
1996
72.5 mm (2.9 in)
1997
123.4 mm (4.9 in)
1998
86.6 mm (3.4 in)
1999
172.7 mm (6.8 in)
2000
80.4 mm (3.2 in)
2001
77.2 mm (3.0 in)
2002
79.5 mm (3.1 in)
2003
95.0 mm (3.7 in)
2004
79.1 mm (3.1 in)
2005
104.2 mm (4.1 in)
2006
169.4 mm (6.7 in)
2007
126.3 mm (5.0 in)
2008
257.0 mm (10.1 in)
2009
111.4 mm (4.4 in)
2010
157.2 mm (6.2 in)
2011
290.6 mm (11.4 in)
2012
186.7 mm (7.4 in)
2013
173.8 mm (6.8 in)
2014
110.5 mm (4.4 in)
2015
146.5 mm (5.8 in)
2016
50.1 mm (2.0 in)
Longest dry spell (CDD)
The longest dry spell of the year at Upper Marlboro 3 NNW, 1956 to 2016. The record is 38 days in 2001, marked on the chart; the median year is 18 days.
Longest dry spell (CDD) at Upper Marlboro 3 NNW by year
Year
Longest dry spell (CDD)
1956
17 days
1957
25 days
1958
19 days
1959
26 days
1960
13 days
1961
15 days
1962
22 days
1963
33 days
1964
31 days
1965
17 days
1966
21 days
1967
19 days
1968
22 days
1969
17 days
1970
17 days
1971
13 days
1972
11 days
1973
17 days
1974
19 days
1975
12 days
1976
17 days
1977
18 days
1978
14 days
1979
12 days
1980
12 days
1981
16 days
1982
16 days
1983
14 days
1984
21 days
1985
24 days
1986
26 days
1987
13 days
1988
21 days
1989
20 days
1990
20 days
1991
19 days
1992
17 days
1993
17 days
1995
29 days
1996
19 days
1997
15 days
1998
25 days
1999
19 days
2000
30 days
2001
38 days
2002
17 days
2003
16 days
2004
17 days
2005
21 days
2006
21 days
2007
34 days
2008
23 days
2009
21 days
2010
17 days
2011
15 days
2012
19 days
2013
16 days
2014
13 days
2015
16 days
2016
9 days
Each chart shows one value per year; the dot marks the record year. TXx is the hottest daily maximum, TNn the coldest daily minimum, Rx1day and Rx5day the largest one-day and five-day rain totals, and CDD the longest run of days with less than 1 mm of rain. A year with missing days can understate an extreme.
Frost Dates and Growing Season
51 years with a frost
Across 51 years with a frost, the median last spring frost at Upper Marlboro 3 NNW falls on 16 April and the median first autumn frost on 19 October, which leaves a median of 188 days between them.
Fitted over all years, the growing season changes by +6.6 days per decade at this station.
Frost dates and growing season at Upper Marlboro 3 NNW
Measure
Median, all years
Earliest period
Recent period (1978 to 2015)
Recent against earliest
Fitted trend
Last spring frost
16 April
n/a
11 April
n/a
-3.4 days per decade
First autumn frost
19 October
n/a
24 October
n/a
+3.2 days per decade
Growing days
188 days
n/a
195 days
n/a
+6.6 days per decade
A frost day is a day with a daily minimum at or below 0 C (32 F). The last spring frost and the first autumn frost are the last and first such days of the cold season, and growing days are the days between them. A negative trend for the last spring frost means it comes earlier.
Rainfall Return Levels
54 years, 1957 to 2015
A day with at least 69.2 mm (2.7 in) of rain is expected about once in 2 years. A day with at least 192.3 mm (7.6 in) of rain is expected about once in 100 years.
Rainfall return levels at Upper Marlboro 3 NNW: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
69.2 mm (2.7 in)
5 years
96.6 mm (3.8 in)
10 years
116.8 mm (4.6 in)
25 years
144.8 mm (5.7 in)
50 years
167.7 mm (6.6 in)
100 years
192.3 mm (7.6 in)
Longer than the 54 years of record
The levels come from a generalised extreme value (GEV) distribution fitted by L-moments to the wettest-day total of each year, 54 years of values from 1957 to 2015.
A return level is an estimate. It is least reliable for the long periods, 50 and 100 years, and for any period longer than the record behind the fit, where the fit has to reach past the largest day actually observed. It is not a forecast.
The largest wettest-day totals in the fit: 189.5 mm (7.5 in) in 2011; 143.5 mm (5.6 in) in 2012; 130.8 mm (5.1 in) in 2008.
Station Changes
1 suspected
One change was suspected in the annual mean temperature of Upper Marlboro 3 NNW, at 1974. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1974 ran 0.2 C (0.4 F) lower than in the years before (possible change).
Suspected changes in the annual mean temperature at Upper Marlboro 3 NNW, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1974
-0.2
-0.4
possible
5
Possible change at the station (a move, a new instrument or a new site); the record is kept as measured. A "likely" change has a larger test statistic than a "possible" one. Neither says why the station differs from its neighbours. How changes are found, and the largest ones.
Download the Data
Data for Upper Marlboro 3 NNW standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Upper Marlboro 3 NNW threshold days by year: CSV or JSON. Field meanings are on the data page.
Source: NOAA National Centers for Environmental Information, Global Historical Climatology Network Daily (GHCN-Daily). Records are computed by World Extreme Weather Monitor and are not official NOAA products. (US Government open data (NOAA NCEI)) Data as of 2026-10-15 (15 October 2026). Records are computed by this site and are not official.