Record envelope, standing records and threshold days for Duncan (USC00342660), Oklahoma, United States, with 90 years of record.
Key Facts for Duncan
Duncan (USC00342660) is a weather station in Oklahoma, United States at 34.51 latitude and -97.93 longitude, 344 m (1,130 ft) above sea level.
The station reports from 1936 to 2025, 90 years of record.
1,464 records set at Duncan still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Duncan set a daily record precipitation of 43.9 mm (1.7 in) on 7 May 2025.
About the Station
Location: Oklahoma, United States, 34.51 latitude, -97.93 longitude.
Elevation: 344 m (1,130 ft).
Period of record: 1936 to 2025, 90 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 Duncan. 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 Duncan, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
28.9 C (84.0 F)
-22.2 C (-8.0 F)
n/a
n/a
Feb
32.2 C (90.0 F)
-18.9 C (-2.0 F)
n/a
n/a
Mar
36.1 C (97.0 F)
-16.7 C (1.9 F)
n/a
n/a
Apr
37.8 C (100.0 F)
-3.3 C (26.1 F)
n/a
n/a
May
40.0 C (104.0 F)
1.1 C (34.0 F)
n/a
n/a
Jun
43.9 C (111.0 F)
8.3 C (46.9 F)
n/a
n/a
Jul
43.3 C (109.9 F)
12.8 C (55.0 F)
n/a
n/a
Aug
43.9 C (111.0 F)
12.8 C (55.0 F)
n/a
n/a
Sep
42.2 C (108.0 F)
2.2 C (36.0 F)
n/a
n/a
Oct
38.9 C (102.0 F)
-7.2 C (19.0 F)
n/a
n/a
Nov
32.2 C (90.0 F)
-10.0 C (14.0 F)
n/a
n/a
Dec
31.1 C (88.0 F)
-18.9 C (-2.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Duncan still stand. 2011 holds the most, with 65.
Standing records at Duncan by the year they were set
Year set
Standing records
1936
8
1937
26
1938
21
1939
35
1940
31
1941
10
1942
16
1943
13
1944
8
1945
23
1946
23
1947
23
1948
30
1949
15
1950
35
1951
26
1952
29
1953
33
1954
36
1955
30
1956
31
1957
17
1958
19
1959
18
1960
16
1961
14
1962
26
1963
30
1964
23
1965
14
1966
24
1967
18
1968
12
1969
14
1970
25
1971
11
1972
20
1973
12
1974
24
1975
9
1976
18
1977
13
1978
15
1979
25
1980
28
1981
9
1982
8
1983
27
1984
15
1985
19
1986
7
1987
2
1988
9
1989
35
1990
15
1991
23
1992
24
1993
17
1994
16
1995
20
1996
24
1997
13
1998
13
1999
4
2000
23
2001
6
2002
8
2003
17
2004
16
2005
14
2006
19
2007
15
2008
17
2009
12
2010
5
2011
65
All-Time Record Progression
9 new records
9 all-time records were set at Duncan between 23 February 1968 and 26 July 2011. Each dot is a new record.
When Duncan set new all-time records
Date
Kind
Detail
1968-02-23
Record daily snowfall
Record daily snowfall 16.0 cm (6.3 in)
1970-08-09
Record high maximum temperature
Record high maximum temperature 43.9 C (111.0 F)
1973-01-09
Record low maximum temperature
Record low maximum temperature -10.0 C (14.0 F)
1979-01-02
Record low maximum temperature
Record low maximum temperature -11.1 C (12.0 F)
1983-12-22
Record low maximum temperature
Record low maximum temperature -12.2 C (10.0 F)
1988-01-07
Record daily snowfall
Record daily snowfall 25.4 cm (10.0 in)
1988-01-07
Record snow depth
Record snow depth 33.0 cm (13.0 in)
1990-12-23
Record low maximum temperature
Record low maximum temperature -13.3 C (8.1 F)
2011-07-26
Record high minimum temperature
Record high minimum temperature 31.1 C (88.0 F)
Wettest Day of Each Month
May: 250.2 mm (9.9 in)
The wettest day on record for each calendar month at Duncan. The most was 250.2 mm (9.9 in) on 19 May 1955.
Record daily precipitation for each month at Duncan
Month
Record daily precipitation (mm)
Date
Jan
53.1 mm (2.1 in)
18 January 2020
Feb
86.9 mm (3.4 in)
15 February 1938
Mar
114.3 mm (4.5 in)
31 March 2007
Apr
110.0 mm (4.3 in)
30 April 2025
May
250.2 mm (9.9 in)
19 May 1955
Jun
136.4 mm (5.4 in)
13 June 2016
Jul
109.7 mm (4.3 in)
14 July 1989
Aug
173.2 mm (6.8 in)
19 August 2007
Sep
158.0 mm (6.2 in)
22 September 2018
Oct
144.8 mm (5.7 in)
30 October 1941
Nov
100.8 mm (4.0 in)
3 November 2024
Dec
71.1 mm (2.8 in)
20 December 1991
Period of Record Coverage
1936 to 2012
Complete yearUnder 90 percent of days
77 years of record at Duncan, 1936 to 2012. 13 years have data for under 90 percent of days and are left out of rankings: 1936, 1943, 1964, 1967, 1973, 1976, 1977, 1978 and others.
Cooler than the station meanWarmer than the station mean
One stripe for each of 63 complete years at Duncan, 1937 to 2011. Blue stripes are years cooler than the station's own mean of 16.8 C (62.3 F); red stripes are warmer. The coolest year was 1993, at 15.5 C (59.9 F), and the warmest was 1954, at 18.8 C (65.9 F). The strongest colour marks a difference of 2.0 C (3.6 F).
Annual mean temperature at Duncan as warming stripes, 1937 to 2011
Year
Annual mean temperature
Difference from the station mean
1937
16.8 C
-0.03 C
1938
18.8 C
+1.97 C
1939
18.6 C
+1.78 C
1940
15.6 C
-1.20 C
1941
16.6 C
-0.28 C
1942
16.2 C
-0.67 C
1944
16.9 C
+0.01 C
1945
16.6 C
-0.24 C
1946
17.9 C
+1.08 C
1947
16.9 C
+0.01 C
1948
16.6 C
-0.25 C
1949
16.5 C
-0.33 C
1950
17.1 C
+0.28 C
1951
17.4 C
+0.53 C
1952
18.1 C
+1.23 C
1953
18.2 C
+1.36 C
1954
18.8 C
+1.98 C
1955
17.5 C
+0.66 C
1956
18.1 C
+1.28 C
1957
16.3 C
-0.50 C
1958
16.6 C
-0.28 C
1959
17.3 C
+0.47 C
1960
16.8 C
-0.02 C
1961
16.7 C
-0.17 C
1963
18.2 C
+1.32 C
1966
16.5 C
-0.35 C
1968
16.2 C
-0.69 C
1969
16.9 C
+0.02 C
1970
17.0 C
+0.15 C
1971
17.2 C
+0.31 C
1972
17.1 C
+0.23 C
1974
17.6 C
+0.75 C
1976
16.1 C
-0.76 C
1977
17.2 C
+0.33 C
1978
15.9 C
-0.93 C
1979
15.7 C
-1.18 C
1980
17.3 C
+0.50 C
1981
17.0 C
+0.14 C
1982
16.5 C
-0.34 C
1983
15.8 C
-1.05 C
1984
16.9 C
+0.09 C
1988
16.1 C
-0.73 C
1989
15.6 C
-1.29 C
1991
16.4 C
-0.43 C
1992
16.2 C
-0.66 C
1993
15.5 C
-1.34 C
1994
16.2 C
-0.60 C
1995
16.2 C
-0.61 C
1996
16.0 C
-0.80 C
1997
15.9 C
-0.97 C
1998
17.7 C
+0.86 C
1999
17.3 C
+0.45 C
2000
16.8 C
-0.08 C
2001
16.7 C
-0.10 C
2003
16.2 C
-0.67 C
2004
16.4 C
-0.49 C
2005
17.0 C
+0.20 C
2006
17.6 C
+0.72 C
2007
16.1 C
-0.75 C
2008
16.5 C
-0.37 C
2009
16.3 C
-0.59 C
2010
16.7 C
-0.16 C
2011
18.1 C
+1.23 C
The annual mean temperature here has fallen by 0.12 C (0.03 to 0.20) per decade over 1937 to 2011. In Fahrenheit: 0.2 F (0.1 to 0.4) per decade. The slope is a straight line fitted to 63 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Duncan
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
-0.11 C (-0.20 to -0.03) per decade
-0.2 F (-0.4 to -0.1) per decade
1937 to 2011
63
Fall
Mean daily maximum
-0.2 C (-0.3 to -0.1) per decade
-0.3 F (-0.5 to -0.1) per decade
1937 to 2011
63
Fall
Mean daily minimum
-0.06 C (-0.13 to 0.01) per decade
-0.10 F (-0.23 to 0.02) per decade
1937 to 2011
63
Not clearly different from zero
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
1936 to 2025
Yearly extremes at Duncan: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
43.9 C (111.0 F)
1970
40.0 C (104.0 F)
77
Coldest night (TNn)
-22.2 C (-8.0 F)
1947
-13.3 C (8.1 F)
77
Wettest day (Rx1day)
250.2 mm (9.9 in)
1955
73.6 mm (2.9 in)
90
Wettest five days (Rx5day)
299.0 mm (11.8 in)
1955
113.6 mm (4.5 in)
90
Longest dry spell (CDD)
74 days
1980
33 days
90
Hottest day (TXx)
The hottest day of the year at Duncan, 1936 to 2025. The record is 43.9 C (111.0 F) in 1970, marked on the chart; the median year is 40.0 C (104.0 F).
Hottest day (TXx) at Duncan by year
Year
Hottest day (TXx)
1936
31.1 C (88.0 F)
1937
42.2 C (108.0 F)
1938
40.6 C (105.1 F)
1939
42.2 C (108.0 F)
1940
38.3 C (100.9 F)
1941
39.4 C (102.9 F)
1942
40.0 C (104.0 F)
1943
33.9 C (93.0 F)
1944
39.4 C (102.9 F)
1945
40.0 C (104.0 F)
1946
43.3 C (109.9 F)
1947
41.7 C (107.1 F)
1948
41.7 C (107.1 F)
1949
38.9 C (102.0 F)
1950
36.7 C (98.1 F)
1951
42.2 C (108.0 F)
1952
41.7 C (107.1 F)
1953
42.2 C (108.0 F)
1954
42.8 C (109.0 F)
1955
38.3 C (100.9 F)
1956
42.2 C (108.0 F)
1957
38.9 C (102.0 F)
1958
38.9 C (102.0 F)
1959
39.4 C (102.9 F)
1960
38.9 C (102.0 F)
1961
39.4 C (102.9 F)
1962
42.2 C (108.0 F)
1963
41.7 C (107.1 F)
1964
43.3 C (109.9 F)
1965
39.4 C (102.9 F)
1966
41.7 C (107.1 F)
1967
38.9 C (102.0 F)
1968
40.0 C (104.0 F)
1969
41.7 C (107.1 F)
1970
43.9 C (111.0 F)
1971
41.7 C (107.1 F)
1972
42.8 C (109.0 F)
1973
37.2 C (99.0 F)
1974
42.2 C (108.0 F)
1975
36.7 C (98.1 F)
1976
40.0 C (104.0 F)
1977
41.1 C (106.0 F)
1978
41.1 C (106.0 F)
1979
38.3 C (100.9 F)
1980
43.9 C (111.0 F)
1981
40.6 C (105.1 F)
1982
39.4 C (102.9 F)
1983
40.0 C (104.0 F)
1984
41.1 C (106.0 F)
1985
39.4 C (102.9 F)
1986
30.0 C (86.0 F)
1987
33.3 C (91.9 F)
1988
39.4 C (102.9 F)
1989
38.3 C (100.9 F)
1990
38.9 C (102.0 F)
1991
37.8 C (100.0 F)
1992
36.7 C (98.1 F)
1993
38.9 C (102.0 F)
1994
39.4 C (102.9 F)
1995
39.4 C (102.9 F)
1996
41.7 C (107.1 F)
1997
37.8 C (100.0 F)
1998
41.1 C (106.0 F)
1999
40.6 C (105.1 F)
2000
42.2 C (108.0 F)
2001
40.6 C (105.1 F)
2002
37.8 C (100.0 F)
2003
39.4 C (102.9 F)
2004
36.1 C (97.0 F)
2005
38.3 C (100.9 F)
2006
40.0 C (104.0 F)
2007
37.2 C (99.0 F)
2008
40.0 C (104.0 F)
2009
38.9 C (102.0 F)
2010
40.6 C (105.1 F)
2011
42.8 C (109.0 F)
2012
22.8 C (73.0 F)
2013
n/a
2014
n/a
2015
n/a
2016
n/a
2017
n/a
2018
n/a
2019
n/a
2020
n/a
2021
n/a
2022
n/a
2023
n/a
2024
n/a
2025
n/a
Coldest night (TNn)
The coldest night of the year at Duncan, 1936 to 2025. The record is -22.2 C (-8.0 F) in 1947, marked on the chart; the median year is -13.3 C (8.1 F).
Coldest night (TNn) at Duncan by year
Year
Coldest night (TNn)
1936
-5.0 C (23.0 F)
1937
-12.2 C (10.0 F)
1938
-11.1 C (12.0 F)
1939
-11.1 C (12.0 F)
1940
-17.2 C (1.0 F)
1941
-6.1 C (21.0 F)
1942
-17.8 C (0.0 F)
1943
-18.3 C (-0.9 F)
1944
-18.3 C (-0.9 F)
1945
-12.2 C (10.0 F)
1946
-11.1 C (12.0 F)
1947
-22.2 C (-8.0 F)
1948
-16.7 C (1.9 F)
1949
-13.3 C (8.1 F)
1950
-13.9 C (7.0 F)
1951
-17.2 C (1.0 F)
1952
-8.3 C (17.1 F)
1953
-12.2 C (10.0 F)
1954
-13.3 C (8.1 F)
1955
-11.1 C (12.0 F)
1956
-11.7 C (10.9 F)
1957
-11.1 C (12.0 F)
1958
-13.9 C (7.0 F)
1959
-17.8 C (0.0 F)
1960
-11.7 C (10.9 F)
1961
-12.8 C (9.0 F)
1962
-17.8 C (0.0 F)
1963
-16.7 C (1.9 F)
1964
-15.6 C (3.9 F)
1965
-12.2 C (10.0 F)
1966
-17.2 C (1.0 F)
1967
-11.1 C (12.0 F)
1968
-15.6 C (3.9 F)
1969
-13.3 C (8.1 F)
1970
-12.8 C (9.0 F)
1971
-14.4 C (6.1 F)
1972
-15.0 C (5.0 F)
1973
-15.0 C (5.0 F)
1974
-12.8 C (9.0 F)
1975
-9.4 C (15.1 F)
1976
-14.4 C (6.1 F)
1977
-18.9 C (-2.0 F)
1978
-13.9 C (7.0 F)
1979
-16.1 C (3.0 F)
1980
-15.6 C (3.9 F)
1981
-15.0 C (5.0 F)
1982
-16.1 C (3.0 F)
1983
-17.8 C (0.0 F)
1984
-15.0 C (5.0 F)
1985
-18.9 C (-2.0 F)
1986
-15.6 C (3.9 F)
1987
-3.9 C (25.0 F)
1988
-20.0 C (-4.0 F)
1989
-18.9 C (-2.0 F)
1990
-15.6 C (3.9 F)
1991
-12.8 C (9.0 F)
1992
-10.0 C (14.0 F)
1993
-10.0 C (14.0 F)
1994
-11.7 C (10.9 F)
1995
-10.6 C (12.9 F)
1996
-17.2 C (1.0 F)
1997
-12.8 C (9.0 F)
1998
-11.7 C (10.9 F)
1999
-11.1 C (12.0 F)
2000
-9.4 C (15.1 F)
2001
-8.9 C (16.0 F)
2002
-12.2 C (10.0 F)
2003
-10.6 C (12.9 F)
2004
-13.9 C (7.0 F)
2005
-13.9 C (7.0 F)
2006
-11.1 C (12.0 F)
2007
-11.7 C (10.9 F)
2008
-11.1 C (12.0 F)
2009
-11.7 C (10.9 F)
2010
-13.3 C (8.1 F)
2011
-17.2 C (1.0 F)
2012
-5.6 C (21.9 F)
2013
n/a
2014
n/a
2015
n/a
2016
n/a
2017
n/a
2018
n/a
2019
n/a
2020
n/a
2021
n/a
2022
n/a
2023
n/a
2024
n/a
2025
n/a
Wettest day (Rx1day)
The wettest day of the year at Duncan, 1936 to 2025. The record is 250.2 mm (9.9 in) in 1955, marked on the chart; the median year is 73.6 mm (2.9 in).
Wettest day (Rx1day) at Duncan by year
Year
Wettest day (Rx1day)
1936
11.4 mm (0.4 in)
1937
57.2 mm (2.3 in)
1938
86.9 mm (3.4 in)
1939
38.1 mm (1.5 in)
1940
69.9 mm (2.8 in)
1941
144.8 mm (5.7 in)
1942
72.4 mm (2.9 in)
1943
94.0 mm (3.7 in)
1944
73.9 mm (2.9 in)
1945
66.0 mm (2.6 in)
1946
89.9 mm (3.5 in)
1947
65.8 mm (2.6 in)
1948
67.1 mm (2.6 in)
1949
47.0 mm (1.9 in)
1950
102.9 mm (4.1 in)
1951
102.9 mm (4.1 in)
1952
58.4 mm (2.3 in)
1953
111.0 mm (4.4 in)
1954
52.1 mm (2.1 in)
1955
250.2 mm (9.9 in)
1956
93.5 mm (3.7 in)
1957
59.7 mm (2.4 in)
1958
52.8 mm (2.1 in)
1959
71.6 mm (2.8 in)
1960
73.2 mm (2.9 in)
1961
50.3 mm (2.0 in)
1962
65.8 mm (2.6 in)
1963
75.7 mm (3.0 in)
1964
74.2 mm (2.9 in)
1965
76.2 mm (3.0 in)
1966
84.1 mm (3.3 in)
1967
80.5 mm (3.2 in)
1968
84.6 mm (3.3 in)
1969
53.6 mm (2.1 in)
1970
112.5 mm (4.4 in)
1971
52.3 mm (2.1 in)
1972
109.2 mm (4.3 in)
1973
61.0 mm (2.4 in)
1974
101.6 mm (4.0 in)
1975
103.4 mm (4.1 in)
1976
63.5 mm (2.5 in)
1977
128.3 mm (5.1 in)
1978
84.3 mm (3.3 in)
1979
64.5 mm (2.5 in)
1980
41.4 mm (1.6 in)
1981
62.2 mm (2.4 in)
1982
113.0 mm (4.4 in)
1983
60.5 mm (2.4 in)
1984
69.9 mm (2.8 in)
1985
111.8 mm (4.4 in)
1986
51.6 mm (2.0 in)
1987
44.5 mm (1.8 in)
1988
91.4 mm (3.6 in)
1989
109.7 mm (4.3 in)
1990
78.7 mm (3.1 in)
1991
86.4 mm (3.4 in)
1992
94.5 mm (3.7 in)
1993
77.5 mm (3.1 in)
1994
99.1 mm (3.9 in)
1995
70.9 mm (2.8 in)
1996
57.2 mm (2.3 in)
1997
80.8 mm (3.2 in)
1998
69.3 mm (2.7 in)
1999
53.6 mm (2.1 in)
2000
82.0 mm (3.2 in)
2001
95.8 mm (3.8 in)
2002
54.4 mm (2.1 in)
2003
50.0 mm (2.0 in)
2004
96.5 mm (3.8 in)
2005
48.0 mm (1.9 in)
2006
95.8 mm (3.8 in)
2007
173.2 mm (6.8 in)
2008
63.5 mm (2.5 in)
2009
53.3 mm (2.1 in)
2010
69.6 mm (2.7 in)
2011
74.9 mm (2.9 in)
2012
53.3 mm (2.1 in)
2013
47.8 mm (1.9 in)
2014
52.3 mm (2.1 in)
2015
66.5 mm (2.6 in)
2016
136.4 mm (5.4 in)
2017
87.4 mm (3.4 in)
2018
158.0 mm (6.2 in)
2019
59.2 mm (2.3 in)
2020
60.7 mm (2.4 in)
2021
83.1 mm (3.3 in)
2022
94.0 mm (3.7 in)
2023
59.4 mm (2.3 in)
2024
103.6 mm (4.1 in)
2025
110.0 mm (4.3 in)
Wettest five days (Rx5day)
The wettest five days of the year at Duncan, 1936 to 2025. The record is 299.0 mm (11.8 in) in 1955, marked on the chart; the median year is 113.6 mm (4.5 in).
Wettest five days (Rx5day) at Duncan by year
Year
Wettest five days (Rx5day)
1936
11.7 mm (0.5 in)
1937
92.0 mm (3.6 in)
1938
187.9 mm (7.4 in)
1939
62.5 mm (2.5 in)
1940
111.6 mm (4.4 in)
1941
163.6 mm (6.4 in)
1942
105.0 mm (4.1 in)
1943
109.2 mm (4.3 in)
1944
106.7 mm (4.2 in)
1945
216.5 mm (8.5 in)
1946
116.3 mm (4.6 in)
1947
94.0 mm (3.7 in)
1948
96.9 mm (3.8 in)
1949
82.4 mm (3.2 in)
1950
239.0 mm (9.4 in)
1951
142.5 mm (5.6 in)
1952
100.3 mm (3.9 in)
1953
152.7 mm (6.0 in)
1954
118.6 mm (4.7 in)
1955
299.0 mm (11.8 in)
1956
115.9 mm (4.6 in)
1957
123.7 mm (4.9 in)
1958
109.4 mm (4.3 in)
1959
97.8 mm (3.9 in)
1960
167.5 mm (6.6 in)
1961
68.1 mm (2.7 in)
1962
131.8 mm (5.2 in)
1963
84.8 mm (3.3 in)
1964
113.0 mm (4.4 in)
1965
114.2 mm (4.5 in)
1966
127.6 mm (5.0 in)
1967
106.9 mm (4.2 in)
1968
102.9 mm (4.1 in)
1969
108.7 mm (4.3 in)
1970
122.7 mm (4.8 in)
1971
53.1 mm (2.1 in)
1972
181.6 mm (7.1 in)
1973
89.7 mm (3.5 in)
1974
121.9 mm (4.8 in)
1975
123.7 mm (4.9 in)
1976
92.7 mm (3.6 in)
1977
173.0 mm (6.8 in)
1978
101.8 mm (4.0 in)
1979
135.9 mm (5.4 in)
1980
77.5 mm (3.1 in)
1981
109.7 mm (4.3 in)
1982
171.4 mm (6.7 in)
1983
202.9 mm (8.0 in)
1984
104.2 mm (4.1 in)
1985
158.6 mm (6.2 in)
1986
73.2 mm (2.9 in)
1987
20.4 mm (0.8 in)
1988
133.8 mm (5.3 in)
1989
223.0 mm (8.8 in)
1990
159.0 mm (6.3 in)
1991
120.4 mm (4.7 in)
1992
98.3 mm (3.9 in)
1993
81.8 mm (3.2 in)
1994
170.4 mm (6.7 in)
1995
130.5 mm (5.1 in)
1996
116.6 mm (4.6 in)
1997
105.4 mm (4.1 in)
1998
79.0 mm (3.1 in)
1999
84.0 mm (3.3 in)
2000
162.8 mm (6.4 in)
2001
101.4 mm (4.0 in)
2002
77.4 mm (3.0 in)
2003
67.3 mm (2.6 in)
2004
116.6 mm (4.6 in)
2005
78.3 mm (3.1 in)
2006
115.9 mm (4.6 in)
2007
212.6 mm (8.4 in)
2008
134.6 mm (5.3 in)
2009
100.1 mm (3.9 in)
2010
86.2 mm (3.4 in)
2011
93.2 mm (3.7 in)
2012
69.8 mm (2.7 in)
2013
67.6 mm (2.7 in)
2014
82.8 mm (3.3 in)
2015
131.8 mm (5.2 in)
2016
177.6 mm (7.0 in)
2017
152.4 mm (6.0 in)
2018
168.9 mm (6.6 in)
2019
105.6 mm (4.2 in)
2020
164.7 mm (6.5 in)
2021
175.2 mm (6.9 in)
2022
99.3 mm (3.9 in)
2023
164.8 mm (6.5 in)
2024
138.7 mm (5.5 in)
2025
194.6 mm (7.7 in)
Longest dry spell (CDD)
The longest dry spell of the year at Duncan, 1936 to 2025. The record is 74 days in 1980, marked on the chart; the median year is 33 days.
Longest dry spell (CDD) at Duncan by year
Year
Longest dry spell (CDD)
1936
33 days
1937
40 days
1938
43 days
1939
33 days
1940
41 days
1941
26 days
1942
26 days
1943
48 days
1944
27 days
1945
41 days
1946
29 days
1947
49 days
1948
30 days
1949
32 days
1950
58 days
1951
28 days
1952
47 days
1953
30 days
1954
47 days
1955
56 days
1956
33 days
1957
29 days
1958
32 days
1959
40 days
1960
38 days
1961
22 days
1962
33 days
1963
36 days
1964
29 days
1965
43 days
1966
44 days
1967
33 days
1968
18 days
1969
29 days
1970
35 days
1971
30 days
1972
40 days
1973
27 days
1974
51 days
1975
20 days
1976
35 days
1977
49 days
1978
33 days
1979
25 days
1980
74 days
1981
31 days
1982
20 days
1983
23 days
1984
29 days
1985
17 days
1986
33 days
1987
20 days
1988
29 days
1989
44 days
1990
25 days
1991
38 days
1992
20 days
1993
19 days
1994
22 days
1995
37 days
1996
59 days
1997
30 days
1998
30 days
1999
35 days
2000
66 days
2001
34 days
2002
29 days
2003
36 days
2004
25 days
2005
36 days
2006
27 days
2007
21 days
2008
36 days
2009
26 days
2010
45 days
2011
58 days
2012
43 days
2013
28 days
2014
33 days
2015
19 days
2016
20 days
2017
32 days
2018
21 days
2019
28 days
2020
41 days
2021
44 days
2022
34 days
2023
39 days
2024
37 days
2025
18 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
63 years with a frost
Across 63 years with a frost, the median last spring frost at Duncan falls on 28 March and the median first autumn frost on 7 November, which leaves a median of 224 days between them.
In 1977 to 2011 the median growing season was 230 days. That is 11 days more than in 1937 to 1971.
Fitted over all years, the growing season changes by +2.1 days per decade at this station.
Frost dates and growing season at Duncan
Measure
Median, all years
Earliest period (1937 to 1971)
Recent period (1977 to 2011)
Recent against earliest
Fitted trend
Last spring frost
28 March
1 April
23 March
9 days earlier
-1.1 days per decade
First autumn frost
7 November
5 November
11 November
6 days later
+0.9 days per decade
Growing days
224 days
219 days
230 days
11 days more
+2.1 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
81 years, 1937 to 2024
A day with at least 73.5 mm (2.9 in) of rain is expected about once in 2 years. A day with at least 198.5 mm (7.8 in) of rain is expected about once in 100 years.
Rainfall return levels at Duncan: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
73.5 mm (2.9 in)
5 years
99.1 mm (3.9 in)
10 years
118.9 mm (4.7 in)
25 years
147.5 mm (5.8 in)
50 years
171.7 mm (6.8 in)
100 years
198.5 mm (7.8 in)
Longer than the 81 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, 81 years of values from 1937 to 2024.
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: 250.2 mm (9.9 in) in 1955; 173.2 mm (6.8 in) in 2007; 158.0 mm (6.2 in) in 2018.
Station Changes
1 suspected
One change was suspected in the annual mean temperature of Duncan, at 1982. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1982 ran 0.3 C (0.5 F) higher than in the years before (likely change).
Suspected changes in the annual mean temperature at Duncan, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1982
+0.3
+0.5
likely
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 Duncan standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Duncan 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.