Record envelope, standing records and threshold days for Ankeny (USC00130241), Iowa, United States, with 72 years of record.
Key Facts for Ankeny
Ankeny (USC00130241) is a weather station in Iowa, United States at 41.73 latitude and -93.65 longitude, 297 m (975 ft) above sea level.
The station reports from 1950 to 2021, 72 years of record.
1,464 records set at Ankeny still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Ankeny set a daily record high minimum temperature of 15.0 C (59.0 F) on 7 April 2021.
About the Station
Location: Iowa, United States, 41.73 latitude, -93.65 longitude.
Elevation: 297 m (975 ft).
Period of record: 1950 to 2021, 72 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 Ankeny. 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 Ankeny, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
19.4 C (66.9 F)
-33.3 C (-27.9 F)
n/a
n/a
Feb
23.3 C (73.9 F)
-36.7 C (-34.1 F)
n/a
n/a
Mar
32.2 C (90.0 F)
-30.6 C (-23.1 F)
n/a
n/a
Apr
33.9 C (93.0 F)
-13.3 C (8.1 F)
n/a
n/a
May
37.2 C (99.0 F)
-3.3 C (26.1 F)
n/a
n/a
Jun
38.9 C (102.0 F)
4.4 C (39.9 F)
n/a
n/a
Jul
40.6 C (105.1 F)
5.6 C (42.1 F)
n/a
n/a
Aug
41.1 C (106.0 F)
3.9 C (39.0 F)
n/a
n/a
Sep
37.8 C (100.0 F)
-5.6 C (21.9 F)
n/a
n/a
Oct
34.4 C (93.9 F)
-15.0 C (5.0 F)
n/a
n/a
Nov
28.3 C (82.9 F)
-21.7 C (-7.1 F)
n/a
n/a
Dec
21.1 C (70.0 F)
-31.7 C (-25.1 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Ankeny still stand. 1988 holds the most, with 35.
Standing records at Ankeny by the year they were set
Year set
Standing records
1950
18
1951
33
1952
18
1953
22
1954
15
1955
33
1956
18
1957
14
1958
20
1959
26
1960
22
1961
18
1962
24
1963
32
1964
27
1965
22
1966
26
1967
25
1968
33
1969
20
1970
27
1971
17
1972
30
1973
5
1974
18
1975
16
1976
16
1977
27
1978
17
1979
13
1980
12
1981
22
1982
24
1983
31
1984
20
1985
18
1986
20
1987
15
1988
35
1989
32
1990
13
1991
28
1992
23
1993
14
1994
17
1995
19
1996
28
1997
16
1998
29
1999
31
2000
22
2001
14
2002
13
2003
19
2004
13
2005
14
2006
31
2007
12
2008
11
2009
12
2010
10
2011
22
2012
35
2013
16
2014
20
2015
11
2016
6
2017
24
2018
14
2019
14
2020
18
2021
14
All-Time Record Progression
10 new records
10 all-time records were set at Ankeny between 10 January 1982 and 1 January 2001. Each dot is a new record.
When Ankeny set new all-time records
Date
Kind
Detail
1982-01-10
Record low maximum temperature
Record low maximum temperature -22.2 C (-8.0 F)
1983-08-16
Record high maximum temperature
Record high maximum temperature 41.1 C (106.0 F)
1983-12-23
Record low maximum temperature
Record low maximum temperature -22.8 C (-9.0 F)
1983-12-24
Record low maximum temperature
Record low maximum temperature -24.4 C (-11.9 F)
1989-12-22
Record low maximum temperature
Record low maximum temperature -25.0 C (-13.0 F)
1996-02-02
Record low minimum temperature
Record low minimum temperature -32.2 C (-26.0 F)
1996-02-03
Record low minimum temperature
Record low minimum temperature -36.7 C (-34.1 F)
2000-12-20
Record snow depth
Record snow depth 53.3 cm (21.0 in)
2000-12-22
Record snow depth
Record snow depth 55.9 cm (22.0 in)
2001-01-01
Record snow depth
Record snow depth 68.6 cm (27.0 in)
Wettest Day of Each Month
Jun: 133.4 mm (5.3 in)
The wettest day on record for each calendar month at Ankeny. The most was 133.4 mm (5.3 in) on 20 June 1954.
Record daily precipitation for each month at Ankeny
Month
Record daily precipitation (mm)
Date
Jan
57.2 mm (2.3 in)
1 January 1995
Feb
40.4 mm (1.6 in)
21 February 1976
Mar
64.0 mm (2.5 in)
13 March 1990
Apr
114.3 mm (4.5 in)
30 April 1986
May
67.3 mm (2.6 in)
11 May 1970
Jun
133.4 mm (5.3 in)
20 June 1954
Jul
99.8 mm (3.9 in)
28 July 2008
Aug
116.6 mm (4.6 in)
28 August 1977
Sep
99.6 mm (3.9 in)
7 September 2007
Oct
73.9 mm (2.9 in)
7 October 2017
Nov
52.1 mm (2.1 in)
4 November 2003
Dec
63.0 mm (2.5 in)
14 December 2015
Period of Record Coverage
1950 to 2021
Complete yearUnder 90 percent of days
72 years of record at Ankeny, 1950 to 2021. 8 years have data for under 90 percent of days and are left out of rankings: 1950, 1973, 1979, 2012, 2014, 2018, 2019, 2021.
Cooler than the station meanWarmer than the station mean
One stripe for each of 57 complete years at Ankeny, 1951 to 2020. Blue stripes are years cooler than the station's own mean of 9.5 C (49.1 F); red stripes are warmer. The coolest year was 1996, at 7.4 C (45.2 F), and the warmest was 1987, at 11.5 C (52.8 F). The strongest colour marks a difference of 2.2 C (4.0 F).
Annual mean temperature at Ankeny as warming stripes, 1951 to 2020
Year
Annual mean temperature
Difference from the station mean
1951
8.2 C
-1.31 C
1952
9.9 C
+0.37 C
1953
10.6 C
+1.08 C
1954
10.2 C
+0.75 C
1955
9.4 C
-0.10 C
1956
9.6 C
+0.09 C
1957
9.2 C
-0.28 C
1958
8.8 C
-0.71 C
1959
8.9 C
-0.61 C
1960
8.4 C
-1.10 C
1961
8.8 C
-0.67 C
1962
9.2 C
-0.33 C
1963
10.2 C
+0.70 C
1964
10.7 C
+1.25 C
1965
9.7 C
+0.21 C
1966
9.5 C
+0.06 C
1967
9.3 C
-0.15 C
1968
8.9 C
-0.62 C
1969
8.1 C
-1.42 C
1970
8.7 C
-0.78 C
1971
9.2 C
-0.33 C
1972
8.0 C
-1.50 C
1974
9.0 C
-0.45 C
1975
9.0 C
-0.46 C
1976
9.2 C
-0.33 C
1977
9.9 C
+0.41 C
1978
8.3 C
-1.22 C
1980
9.9 C
+0.41 C
1981
10.7 C
+1.21 C
1982
8.8 C
-0.71 C
1983
9.5 C
+0.04 C
1984
9.6 C
+0.13 C
1985
8.9 C
-0.63 C
1986
10.5 C
+1.03 C
1987
11.5 C
+2.06 C
1988
10.4 C
+0.96 C
1990
9.6 C
+0.13 C
1991
9.3 C
-0.20 C
1992
8.9 C
-0.58 C
1994
8.6 C
-0.85 C
1995
8.4 C
-1.08 C
1996
7.4 C
-2.13 C
1997
8.4 C
-1.12 C
1998
10.5 C
+1.06 C
2000
9.8 C
+0.31 C
2002
9.8 C
+0.30 C
2003
9.5 C
+0.03 C
2004
9.6 C
+0.13 C
2005
10.4 C
+0.91 C
2006
10.8 C
+1.27 C
2007
10.1 C
+0.64 C
2009
8.8 C
-0.65 C
2011
10.1 C
+0.57 C
2015
9.8 C
+0.33 C
2016
10.9 C
+1.37 C
2017
11.0 C
+1.51 C
2020
10.3 C
+0.81 C
The annual mean temperature here has risen by 0.12 C (0.01 to 0.24) per decade over 1951 to 2020. In Fahrenheit: 0.22 F (0.02 to 0.43) per decade. The slope is a straight line fitted to 57 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Ankeny
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.12 C (0.01 to 0.24) per decade
0.22 F (0.02 to 0.43) per decade
1951 to 2020
57
Rise
Mean daily maximum
0.18 C (0.05 to 0.31) per decade
0.3 F (0.1 to 0.6) per decade
1951 to 2020
57
Rise
Mean daily minimum
0.1 C (-0.1 to 0.2) per decade
0.1 F (-0.1 to 0.3) per decade
1951 to 2020
57
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
1950 to 2021
Yearly extremes at Ankeny: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
41.1 C (106.0 F)
1983
36.7 C (98.1 F)
72
Coldest night (TNn)
-36.7 C (-34.1 F)
1996
-26.1 C (-15.0 F)
72
Wettest day (Rx1day)
133.4 mm (5.3 in)
1954
61.0 mm (2.4 in)
72
Wettest five days (Rx5day)
255.8 mm (10.1 in)
2010
96.8 mm (3.8 in)
72
Longest dry spell (CDD)
76 days
1952
24 days
72
Hottest day (TXx)
The hottest day of the year at Ankeny, 1950 to 2021. The record is 41.1 C (106.0 F) in 1983, marked on the chart; the median year is 36.7 C (98.1 F).
Hottest day (TXx) at Ankeny by year
Year
Hottest day (TXx)
1950
33.3 C (91.9 F)
1951
34.4 C (93.9 F)
1952
36.1 C (97.0 F)
1953
36.1 C (97.0 F)
1954
37.2 C (99.0 F)
1955
37.8 C (100.0 F)
1956
38.9 C (102.0 F)
1957
38.3 C (100.9 F)
1958
33.9 C (93.0 F)
1959
34.4 C (93.9 F)
1960
35.6 C (96.1 F)
1961
33.9 C (93.0 F)
1962
33.9 C (93.0 F)
1963
37.2 C (99.0 F)
1964
35.6 C (96.1 F)
1965
35.6 C (96.1 F)
1966
36.1 C (97.0 F)
1967
36.7 C (98.1 F)
1968
34.4 C (93.9 F)
1969
34.4 C (93.9 F)
1970
36.7 C (98.1 F)
1971
36.7 C (98.1 F)
1972
35.0 C (95.0 F)
1973
30.6 C (87.1 F)
1974
37.8 C (100.0 F)
1975
35.0 C (95.0 F)
1976
35.6 C (96.1 F)
1977
38.9 C (102.0 F)
1978
36.7 C (98.1 F)
1979
36.1 C (97.0 F)
1980
38.9 C (102.0 F)
1981
36.7 C (98.1 F)
1982
36.1 C (97.0 F)
1983
41.1 C (106.0 F)
1984
37.8 C (100.0 F)
1985
38.9 C (102.0 F)
1986
35.0 C (95.0 F)
1987
36.7 C (98.1 F)
1988
39.4 C (102.9 F)
1989
36.7 C (98.1 F)
1990
36.7 C (98.1 F)
1991
35.6 C (96.1 F)
1992
32.2 C (90.0 F)
1993
32.2 C (90.0 F)
1994
35.0 C (95.0 F)
1995
38.3 C (100.9 F)
1996
35.0 C (95.0 F)
1997
36.1 C (97.0 F)
1998
36.7 C (98.1 F)
1999
39.4 C (102.9 F)
2000
36.7 C (98.1 F)
2001
37.8 C (100.0 F)
2002
37.2 C (99.0 F)
2003
39.4 C (102.9 F)
2004
34.4 C (93.9 F)
2005
37.2 C (99.0 F)
2006
38.3 C (100.9 F)
2007
36.7 C (98.1 F)
2008
36.7 C (98.1 F)
2009
37.8 C (100.0 F)
2010
37.2 C (99.0 F)
2011
40.6 C (105.1 F)
2012
36.7 C (98.1 F)
2013
38.9 C (102.0 F)
2014
33.9 C (93.0 F)
2015
33.9 C (93.0 F)
2016
34.4 C (93.9 F)
2017
37.2 C (99.0 F)
2018
28.3 C (82.9 F)
2019
35.6 C (96.1 F)
2020
35.6 C (96.1 F)
2021
27.2 C (81.0 F)
Coldest night (TNn)
The coldest night of the year at Ankeny, 1950 to 2021. The record is -36.7 C (-34.1 F) in 1996, marked on the chart; the median year is -26.1 C (-15.0 F).
Coldest night (TNn) at Ankeny by year
Year
Coldest night (TNn)
1950
-23.9 C (-11.0 F)
1951
-26.7 C (-16.1 F)
1952
-25.6 C (-14.1 F)
1953
-23.3 C (-9.9 F)
1954
-26.7 C (-16.1 F)
1955
-28.9 C (-20.0 F)
1956
-27.2 C (-17.0 F)
1957
-31.7 C (-25.1 F)
1958
-30.0 C (-22.0 F)
1959
-26.1 C (-15.0 F)
1960
-27.8 C (-18.0 F)
1961
-26.1 C (-15.0 F)
1962
-30.6 C (-23.1 F)
1963
-29.4 C (-20.9 F)
1964
-23.3 C (-9.9 F)
1965
-25.0 C (-13.0 F)
1966
-30.0 C (-22.0 F)
1967
-26.1 C (-15.0 F)
1968
-27.8 C (-18.0 F)
1969
-25.6 C (-14.1 F)
1970
-31.7 C (-25.1 F)
1971
-27.8 C (-18.0 F)
1972
-27.8 C (-18.0 F)
1973
-23.3 C (-9.9 F)
1974
-31.7 C (-25.1 F)
1975
-27.8 C (-18.0 F)
1976
-26.1 C (-15.0 F)
1977
-28.9 C (-20.0 F)
1978
-25.6 C (-14.1 F)
1979
-31.7 C (-25.1 F)
1980
-23.9 C (-11.0 F)
1981
-27.8 C (-18.0 F)
1982
-31.7 C (-25.1 F)
1983
-30.0 C (-22.0 F)
1984
-28.3 C (-18.9 F)
1985
-30.0 C (-22.0 F)
1986
-24.4 C (-11.9 F)
1987
-22.2 C (-8.0 F)
1988
-26.7 C (-16.1 F)
1989
-31.7 C (-25.1 F)
1990
-25.0 C (-13.0 F)
1991
-27.2 C (-17.0 F)
1992
-22.8 C (-9.0 F)
1993
-23.9 C (-11.0 F)
1994
-28.9 C (-20.0 F)
1995
-22.2 C (-8.0 F)
1996
-36.7 C (-34.1 F)
1997
-25.0 C (-13.0 F)
1998
-26.7 C (-16.1 F)
1999
-29.4 C (-20.9 F)
2000
-26.1 C (-15.0 F)
2001
-22.2 C (-8.0 F)
2002
-19.4 C (-2.9 F)
2003
-25.0 C (-13.0 F)
2004
-25.0 C (-13.0 F)
2005
-24.4 C (-11.9 F)
2006
-24.4 C (-11.9 F)
2007
-22.2 C (-8.0 F)
2008
-24.4 C (-11.9 F)
2009
-33.3 C (-27.9 F)
2010
-23.9 C (-11.0 F)
2011
-22.8 C (-9.0 F)
2012
-18.9 C (-2.0 F)
2013
-21.1 C (-6.0 F)
2014
-26.7 C (-16.1 F)
2015
-27.2 C (-17.0 F)
2016
-25.6 C (-14.1 F)
2017
-23.9 C (-11.0 F)
2018
-29.4 C (-20.9 F)
2019
-18.3 C (-0.9 F)
2020
-23.9 C (-11.0 F)
2021
-28.3 C (-18.9 F)
Wettest day (Rx1day)
The wettest day of the year at Ankeny, 1950 to 2021. The record is 133.4 mm (5.3 in) in 1954, marked on the chart; the median year is 61.0 mm (2.4 in).
Wettest day (Rx1day) at Ankeny by year
Year
Wettest day (Rx1day)
1950
48.0 mm (1.9 in)
1951
69.1 mm (2.7 in)
1952
76.7 mm (3.0 in)
1953
61.0 mm (2.4 in)
1954
133.4 mm (5.3 in)
1955
51.8 mm (2.0 in)
1956
36.8 mm (1.4 in)
1957
38.4 mm (1.5 in)
1958
73.7 mm (2.9 in)
1959
61.0 mm (2.4 in)
1960
48.0 mm (1.9 in)
1961
93.7 mm (3.7 in)
1962
31.2 mm (1.2 in)
1963
91.2 mm (3.6 in)
1964
56.4 mm (2.2 in)
1965
44.5 mm (1.8 in)
1966
75.7 mm (3.0 in)
1967
42.4 mm (1.7 in)
1968
43.2 mm (1.7 in)
1969
51.6 mm (2.0 in)
1970
67.3 mm (2.6 in)
1971
51.1 mm (2.0 in)
1972
45.5 mm (1.8 in)
1973
58.2 mm (2.3 in)
1974
76.5 mm (3.0 in)
1975
44.2 mm (1.7 in)
1976
52.3 mm (2.1 in)
1977
116.6 mm (4.6 in)
1978
53.3 mm (2.1 in)
1979
61.2 mm (2.4 in)
1980
71.1 mm (2.8 in)
1981
61.2 mm (2.4 in)
1982
72.4 mm (2.9 in)
1983
99.1 mm (3.9 in)
1984
92.5 mm (3.6 in)
1985
43.7 mm (1.7 in)
1986
114.3 mm (4.5 in)
1987
63.8 mm (2.5 in)
1988
43.4 mm (1.7 in)
1989
41.1 mm (1.6 in)
1990
64.0 mm (2.5 in)
1991
59.4 mm (2.3 in)
1992
74.9 mm (2.9 in)
1993
94.0 mm (3.7 in)
1994
50.8 mm (2.0 in)
1995
57.2 mm (2.3 in)
1996
49.8 mm (2.0 in)
1997
55.9 mm (2.2 in)
1998
61.0 mm (2.4 in)
1999
63.5 mm (2.5 in)
2000
59.2 mm (2.3 in)
2001
58.4 mm (2.3 in)
2002
51.3 mm (2.0 in)
2003
53.1 mm (2.1 in)
2004
53.6 mm (2.1 in)
2005
57.2 mm (2.3 in)
2006
68.6 mm (2.7 in)
2007
99.6 mm (3.9 in)
2008
99.8 mm (3.9 in)
2009
74.2 mm (2.9 in)
2010
93.0 mm (3.7 in)
2011
53.3 mm (2.1 in)
2012
72.6 mm (2.9 in)
2013
87.6 mm (3.4 in)
2014
73.4 mm (2.9 in)
2015
98.3 mm (3.9 in)
2016
82.6 mm (3.3 in)
2017
73.9 mm (2.9 in)
2018
24.9 mm (1.0 in)
2019
62.2 mm (2.4 in)
2020
64.0 mm (2.5 in)
2021
25.7 mm (1.0 in)
Wettest five days (Rx5day)
The wettest five days of the year at Ankeny, 1950 to 2021. The record is 255.8 mm (10.1 in) in 2010, marked on the chart; the median year is 96.8 mm (3.8 in).
Wettest five days (Rx5day) at Ankeny by year
Year
Wettest five days (Rx5day)
1950
63.2 mm (2.5 in)
1951
93.9 mm (3.7 in)
1952
112.5 mm (4.4 in)
1953
82.8 mm (3.3 in)
1954
172.8 mm (6.8 in)
1955
92.0 mm (3.6 in)
1956
74.9 mm (2.9 in)
1957
105.7 mm (4.2 in)
1958
119.9 mm (4.7 in)
1959
89.6 mm (3.5 in)
1960
88.6 mm (3.5 in)
1961
101.6 mm (4.0 in)
1962
63.0 mm (2.5 in)
1963
129.1 mm (5.1 in)
1964
94.8 mm (3.7 in)
1965
80.6 mm (3.2 in)
1966
118.9 mm (4.7 in)
1967
114.8 mm (4.5 in)
1968
82.7 mm (3.3 in)
1969
77.2 mm (3.0 in)
1970
137.9 mm (5.4 in)
1971
79.7 mm (3.1 in)
1972
88.4 mm (3.5 in)
1973
93.0 mm (3.7 in)
1974
81.6 mm (3.2 in)
1975
96.8 mm (3.8 in)
1976
107.2 mm (4.2 in)
1977
150.2 mm (5.9 in)
1978
89.6 mm (3.5 in)
1979
89.8 mm (3.5 in)
1980
90.9 mm (3.6 in)
1981
70.1 mm (2.8 in)
1982
142.0 mm (5.6 in)
1983
196.9 mm (7.8 in)
1984
132.4 mm (5.2 in)
1985
68.9 mm (2.7 in)
1986
132.9 mm (5.2 in)
1987
101.9 mm (4.0 in)
1988
64.5 mm (2.5 in)
1989
65.2 mm (2.6 in)
1990
128.3 mm (5.1 in)
1991
112.0 mm (4.4 in)
1992
98.5 mm (3.9 in)
1993
152.9 mm (6.0 in)
1994
58.8 mm (2.3 in)
1995
76.3 mm (3.0 in)
1996
96.5 mm (3.8 in)
1997
79.3 mm (3.1 in)
1998
100.9 mm (4.0 in)
1999
72.9 mm (2.9 in)
2000
80.1 mm (3.2 in)
2001
77.3 mm (3.0 in)
2002
92.4 mm (3.6 in)
2003
109.5 mm (4.3 in)
2004
113.8 mm (4.5 in)
2005
135.4 mm (5.3 in)
2006
88.7 mm (3.5 in)
2007
117.1 mm (4.6 in)
2008
138.4 mm (5.4 in)
2009
125.2 mm (4.9 in)
2010
255.8 mm (10.1 in)
2011
96.0 mm (3.8 in)
2012
96.8 mm (3.8 in)
2013
100.3 mm (3.9 in)
2014
134.1 mm (5.3 in)
2015
122.0 mm (4.8 in)
2016
158.6 mm (6.2 in)
2017
97.7 mm (3.8 in)
2018
26.7 mm (1.1 in)
2019
99.9 mm (3.9 in)
2020
99.6 mm (3.9 in)
2021
35.1 mm (1.4 in)
Longest dry spell (CDD)
The longest dry spell of the year at Ankeny, 1950 to 2021. The record is 76 days in 1952, marked on the chart; the median year is 24 days.
Longest dry spell (CDD) at Ankeny by year
Year
Longest dry spell (CDD)
1950
31 days
1951
17 days
1952
76 days
1953
36 days
1954
45 days
1955
29 days
1956
23 days
1957
18 days
1958
29 days
1959
26 days
1960
27 days
1961
22 days
1962
35 days
1963
28 days
1964
21 days
1965
20 days
1966
26 days
1967
45 days
1968
38 days
1969
19 days
1970
22 days
1971
31 days
1972
27 days
1973
15 days
1974
25 days
1975
22 days
1976
31 days
1977
22 days
1978
21 days
1979
30 days
1980
28 days
1981
30 days
1982
18 days
1983
22 days
1984
22 days
1985
24 days
1986
30 days
1987
49 days
1988
30 days
1989
32 days
1990
19 days
1991
23 days
1992
22 days
1993
22 days
1994
23 days
1995
24 days
1996
26 days
1997
18 days
1998
23 days
1999
25 days
2000
21 days
2001
17 days
2002
50 days
2003
20 days
2004
19 days
2005
31 days
2006
26 days
2007
30 days
2008
13 days
2009
24 days
2010
26 days
2011
20 days
2012
19 days
2013
19 days
2014
23 days
2015
26 days
2016
20 days
2017
35 days
2018
15 days
2019
18 days
2020
19 days
2021
19 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
57 years with a frost
Across 57 years with a frost, the median last spring frost at Ankeny falls on 25 April and the median first autumn frost on 7 October, which leaves a median of 164 days between them.
Fitted over all years, the growing season changes by +1.2 days per decade at this station.
Frost dates and growing season at Ankeny
Measure
Median, all years
Earliest period
Recent period (1980 to 2020)
Recent against earliest
Fitted trend
Last spring frost
25 April
n/a
23 April
n/a
-0.7 days per decade
First autumn frost
7 October
n/a
7 October
n/a
+0.4 days per decade
Growing days
164 days
n/a
164 days
n/a
+1.2 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
65 years, 1951 to 2020
A day with at least 62.4 mm (2.5 in) of rain is expected about once in 2 years. A day with at least 138.3 mm (5.4 in) of rain is expected about once in 100 years.
Rainfall return levels at Ankeny: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
62.4 mm (2.5 in)
5 years
81.6 mm (3.2 in)
10 years
94.8 mm (3.7 in)
25 years
111.9 mm (4.4 in)
50 years
125.0 mm (4.9 in)
100 years
138.3 mm (5.4 in)
Longer than the 65 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, 65 years of values from 1951 to 2020.
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: 133.4 mm (5.3 in) in 1954; 116.6 mm (4.6 in) in 1977; 114.3 mm (4.5 in) in 1986.
Station Changes
No change in the annual mean temperature of this station was found against its neighbours.
Download the Data
Data for Ankeny standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Ankeny 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 2026-10-14 (14 October 2026). Records are computed by this site and are not official.