Record envelope, standing records and threshold days for Afton (USC00130064), Iowa, United States, with 57 years of record.
Key Facts for Afton
Afton (USC00130064) is a weather station in Iowa, United States at 41.03 latitude and -94.20 longitude, 366 m (1,201 ft) above sea level.
The station reports from 1894 to 1950, 57 years of record.
1,464 records set at Afton still stand.
Records are tracked for tmax, tmin, prcp, snow: an element needs 30 years of data to be eligible.
Afton set a daily record precipitation of 11.4 mm (0.4 in) on 13 January 1950.
About the Station
Location: Iowa, United States, 41.03 latitude, -94.20 longitude.
Elevation: 366 m (1,201 ft).
Period of record: 1894 to 1950, 57 years.
Eligible elements: tmax, tmin, prcp, snow.
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 Afton. 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 Afton, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
17.2 C (63.0 F)
-34.4 C (-29.9 F)
n/a
n/a
Feb
26.1 C (79.0 F)
-31.7 C (-25.1 F)
n/a
n/a
Mar
31.1 C (88.0 F)
-25.0 C (-13.0 F)
n/a
n/a
Apr
34.4 C (93.9 F)
-11.7 C (10.9 F)
n/a
n/a
May
38.3 C (100.9 F)
-5.0 C (23.0 F)
n/a
n/a
Jun
39.4 C (102.9 F)
1.1 C (34.0 F)
n/a
n/a
Jul
44.4 C (111.9 F)
7.2 C (45.0 F)
n/a
n/a
Aug
43.9 C (111.0 F)
3.3 C (37.9 F)
n/a
n/a
Sep
40.6 C (105.1 F)
-4.4 C (24.1 F)
n/a
n/a
Oct
33.3 C (91.9 F)
-15.6 C (3.9 F)
n/a
n/a
Nov
27.8 C (82.0 F)
-20.6 C (-5.1 F)
n/a
n/a
Dec
20.6 C (69.1 F)
-32.8 C (-27.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Afton still stand. 1934 holds the most, with 60.
Standing records at Afton by the year they were set
Year set
Standing records
1894
15
1895
29
1896
31
1897
33
1898
28
1899
33
1900
15
1901
27
1902
27
1903
27
1904
19
1905
21
1906
18
1907
24
1908
14
1909
27
1910
25
1911
31
1912
26
1913
42
1914
23
1915
26
1916
21
1917
33
1918
25
1919
14
1920
20
1921
25
1922
11
1923
21
1924
29
1925
39
1926
15
1927
22
1928
30
1929
17
1930
39
1931
40
1932
29
1933
33
1934
60
1935
26
1936
60
1937
28
1938
24
1939
40
1940
17
1941
16
1942
25
1943
23
1944
27
1945
16
1946
25
1947
17
1948
16
1949
20
All-Time Record Progression
3 new records
3 all-time records were set at Afton between 28 June 1931 and 25 July 1936. Each dot is a new record.
When Afton set new all-time records
Date
Kind
Detail
1931-06-28
Record high minimum temperature
Record high minimum temperature 28.9 C (84.0 F)
1934-08-08
Record high maximum temperature
Record high maximum temperature 43.9 C (111.0 F)
1936-07-25
Record high maximum temperature
Record high maximum temperature 44.4 C (111.9 F)
Wettest Day of Each Month
Aug: 236.2 mm (9.3 in)
The wettest day on record for each calendar month at Afton. The most was 236.2 mm (9.3 in) on 27 August 1903.
Record daily precipitation for each month at Afton
Month
Record daily precipitation (mm)
Date
Jan
36.1 mm (1.4 in)
20 January 1904
Feb
50.8 mm (2.0 in)
17 February 1911
Mar
100.6 mm (4.0 in)
31 March 1897
Apr
88.1 mm (3.5 in)
24 April 1897
May
94.2 mm (3.7 in)
26 May 1915
Jun
109.7 mm (4.3 in)
24 June 1949
Jul
96.0 mm (3.8 in)
28 July 1915
Aug
236.2 mm (9.3 in)
27 August 1903
Sep
134.9 mm (5.3 in)
14 September 1914
Oct
79.0 mm (3.1 in)
31 October 1900
Nov
85.1 mm (3.4 in)
23 November 1931
Dec
40.6 mm (1.6 in)
3 December 1897
Period of Record Coverage
1894 to 1950
Complete yearUnder 90 percent of days
57 years of record at Afton, 1894 to 1950. 5 years have data for under 90 percent of days and are left out of rankings: 1894, 1904, 1929, 1930, 1950.
Cooler than the station meanWarmer than the station mean
One stripe for each of 38 complete years at Afton, 1895 to 1948. Blue stripes are years cooler than the station's own mean of 10.4 C (50.6 F); red stripes are warmer. The coolest year was 1917, at 8.8 C (47.8 F), and the warmest was 1931, at 12.8 C (55.1 F). The strongest colour marks a difference of 2.5 C (4.5 F).
Annual mean temperature at Afton as warming stripes, 1895 to 1948
Year
Annual mean temperature
Difference from the station mean
1895
9.1 C
-1.21 C
1896
10.2 C
-0.15 C
1897
10.0 C
-0.35 C
1898
9.8 C
-0.60 C
1900
10.4 C
0.00 C
1901
9.9 C
-0.43 C
1902
9.5 C
-0.84 C
1903
9.5 C
-0.85 C
1906
10.2 C
-0.18 C
1907
9.8 C
-0.59 C
1908
10.6 C
+0.29 C
1909
9.8 C
-0.58 C
1912
8.8 C
-1.53 C
1914
10.7 C
+0.38 C
1917
8.8 C
-1.59 C
1921
12.4 C
+2.01 C
1922
11.0 C
+0.69 C
1923
10.6 C
+0.21 C
1924
9.3 C
-1.09 C
1925
10.8 C
+0.43 C
1926
10.3 C
-0.05 C
1928
10.7 C
+0.32 C
1931
12.8 C
+2.46 C
1932
10.0 C
-0.32 C
1933
11.5 C
+1.17 C
1934
12.2 C
+1.84 C
1936
10.3 C
-0.05 C
1937
9.8 C
-0.59 C
1938
11.8 C
+1.49 C
1939
11.9 C
+1.55 C
1940
9.8 C
-0.59 C
1941
11.5 C
+1.10 C
1942
10.3 C
-0.10 C
1943
9.5 C
-0.85 C
1944
9.9 C
-0.47 C
1945
9.2 C
-1.13 C
1946
11.4 C
+1.03 C
1948
9.7 C
-0.67 C
The fitted trend in annual mean temperature here over 1895 to 1948 is 0.18 C (-0.01 to 0.37) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: 0.33 F (-0.01 to 0.67) per decade. The slope is a straight line fitted to 38 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Afton
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.18 C (-0.01 to 0.37) per decade
0.33 F (-0.01 to 0.67) per decade
1895 to 1948
38
Not clearly different from zero
Mean daily maximum
0.1 C (-0.1 to 0.3) per decade
0.2 F (-0.1 to 0.6) per decade
1895 to 1948
38
Not clearly different from zero
Mean daily minimum
0.24 C (0.04 to 0.43) per decade
0.4 F (0.1 to 0.8) per decade
1895 to 1948
38
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
1894 to 1950
Yearly extremes at Afton: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
44.4 C (111.9 F)
1936
37.8 C (100.0 F)
57
Coldest night (TNn)
-34.4 C (-29.9 F)
1912
-25.6 C (-14.1 F)
57
Wettest day (Rx1day)
236.2 mm (9.3 in)
1903
67.8 mm (2.7 in)
57
Wettest five days (Rx5day)
263.4 mm (10.4 in)
1903
106.2 mm (4.2 in)
57
Longest dry spell (CDD)
52 days
1904
27 days
57
Hottest day (TXx)
The hottest day of the year at Afton, 1894 to 1950. The record is 44.4 C (111.9 F) in 1936, marked on the chart; the median year is 37.8 C (100.0 F).
Hottest day (TXx) at Afton by year
Year
Hottest day (TXx)
1894
41.7 C (107.1 F)
1895
36.7 C (98.1 F)
1896
36.7 C (98.1 F)
1897
40.6 C (105.1 F)
1898
38.3 C (100.9 F)
1899
36.7 C (98.1 F)
1900
36.7 C (98.1 F)
1901
41.7 C (107.1 F)
1902
35.0 C (95.0 F)
1903
36.1 C (97.0 F)
1904
34.4 C (93.9 F)
1905
36.7 C (98.1 F)
1906
36.7 C (98.1 F)
1907
35.6 C (96.1 F)
1908
35.6 C (96.1 F)
1909
37.2 C (99.0 F)
1910
37.2 C (99.0 F)
1911
40.6 C (105.1 F)
1912
35.6 C (96.1 F)
1913
40.6 C (105.1 F)
1914
41.1 C (106.0 F)
1915
33.9 C (93.0 F)
1916
39.4 C (102.9 F)
1917
37.8 C (100.0 F)
1918
43.3 C (109.9 F)
1919
36.7 C (98.1 F)
1920
36.1 C (97.0 F)
1921
37.8 C (100.0 F)
1922
38.3 C (100.9 F)
1923
37.8 C (100.0 F)
1924
36.1 C (97.0 F)
1925
39.4 C (102.9 F)
1926
38.3 C (100.9 F)
1927
37.8 C (100.0 F)
1928
35.6 C (96.1 F)
1929
36.7 C (98.1 F)
1930
41.1 C (106.0 F)
1931
42.2 C (108.0 F)
1932
37.8 C (100.0 F)
1933
39.4 C (102.9 F)
1934
43.9 C (111.0 F)
1935
38.3 C (100.9 F)
1936
44.4 C (111.9 F)
1937
38.3 C (100.9 F)
1938
38.9 C (102.0 F)
1939
40.6 C (105.1 F)
1940
41.7 C (107.1 F)
1941
40.6 C (105.1 F)
1942
36.7 C (98.1 F)
1943
35.0 C (95.0 F)
1944
35.6 C (96.1 F)
1945
37.2 C (99.0 F)
1946
35.0 C (95.0 F)
1947
38.3 C (100.9 F)
1948
36.1 C (97.0 F)
1949
35.0 C (95.0 F)
1950
11.1 C (52.0 F)
Coldest night (TNn)
The coldest night of the year at Afton, 1894 to 1950. The record is -34.4 C (-29.9 F) in 1912, marked on the chart; the median year is -25.6 C (-14.1 F).
Coldest night (TNn) at Afton by year
Year
Coldest night (TNn)
1894
-22.8 C (-9.0 F)
1895
-29.4 C (-20.9 F)
1896
-23.3 C (-9.9 F)
1897
-26.7 C (-16.1 F)
1898
-23.9 C (-11.0 F)
1899
-26.7 C (-16.1 F)
1900
-23.9 C (-11.0 F)
1901
-27.2 C (-17.0 F)
1902
-27.2 C (-17.0 F)
1903
-25.6 C (-14.1 F)
1904
-27.8 C (-18.0 F)
1905
-31.7 C (-25.1 F)
1906
-22.2 C (-8.0 F)
1907
-26.1 C (-15.0 F)
1908
-22.2 C (-8.0 F)
1909
-25.6 C (-14.1 F)
1910
-25.0 C (-13.0 F)
1911
-25.6 C (-14.1 F)
1912
-34.4 C (-29.9 F)
1913
-23.9 C (-11.0 F)
1914
-26.1 C (-15.0 F)
1915
-29.4 C (-20.9 F)
1916
-28.3 C (-18.9 F)
1917
-30.6 C (-23.1 F)
1918
-30.0 C (-22.0 F)
1919
-28.9 C (-20.0 F)
1920
-22.8 C (-9.0 F)
1921
-20.6 C (-5.1 F)
1922
-21.7 C (-7.1 F)
1923
-23.3 C (-9.9 F)
1924
-32.8 C (-27.0 F)
1925
-24.4 C (-11.9 F)
1926
-24.4 C (-11.9 F)
1927
-23.9 C (-11.0 F)
1928
-23.3 C (-9.9 F)
1929
-26.7 C (-16.1 F)
1930
-28.3 C (-18.9 F)
1931
-19.4 C (-2.9 F)
1932
-26.7 C (-16.1 F)
1933
-28.3 C (-18.9 F)
1934
-22.8 C (-9.0 F)
1935
-24.4 C (-11.9 F)
1936
-29.4 C (-20.9 F)
1937
-21.1 C (-6.0 F)
1938
-22.8 C (-9.0 F)
1939
-23.3 C (-9.9 F)
1940
-30.0 C (-22.0 F)
1941
-17.8 C (0.0 F)
1942
-28.9 C (-20.0 F)
1943
-28.3 C (-18.9 F)
1944
-27.2 C (-17.0 F)
1945
-24.4 C (-11.9 F)
1946
-22.8 C (-9.0 F)
1947
-24.4 C (-11.9 F)
1948
-28.9 C (-20.0 F)
1949
-26.1 C (-15.0 F)
1950
-23.3 C (-9.9 F)
Wettest day (Rx1day)
The wettest day of the year at Afton, 1894 to 1950. The record is 236.2 mm (9.3 in) in 1903, marked on the chart; the median year is 67.8 mm (2.7 in).
Wettest day (Rx1day) at Afton by year
Year
Wettest day (Rx1day)
1894
38.1 mm (1.5 in)
1895
111.8 mm (4.4 in)
1896
74.4 mm (2.9 in)
1897
100.6 mm (4.0 in)
1898
43.2 mm (1.7 in)
1899
53.3 mm (2.1 in)
1900
89.7 mm (3.5 in)
1901
47.0 mm (1.9 in)
1902
75.2 mm (3.0 in)
1903
236.2 mm (9.3 in)
1904
55.9 mm (2.2 in)
1905
53.6 mm (2.1 in)
1906
51.8 mm (2.0 in)
1907
55.6 mm (2.2 in)
1908
52.3 mm (2.1 in)
1909
81.0 mm (3.2 in)
1910
95.5 mm (3.8 in)
1911
50.8 mm (2.0 in)
1912
67.8 mm (2.7 in)
1913
53.6 mm (2.1 in)
1914
134.9 mm (5.3 in)
1915
96.0 mm (3.8 in)
1916
67.3 mm (2.6 in)
1917
52.1 mm (2.1 in)
1918
57.2 mm (2.3 in)
1919
76.2 mm (3.0 in)
1920
81.5 mm (3.2 in)
1921
76.7 mm (3.0 in)
1922
112.0 mm (4.4 in)
1923
39.6 mm (1.6 in)
1924
103.1 mm (4.1 in)
1925
64.8 mm (2.6 in)
1926
50.8 mm (2.0 in)
1927
53.8 mm (2.1 in)
1928
61.2 mm (2.4 in)
1929
39.4 mm (1.6 in)
1930
105.2 mm (4.1 in)
1931
85.1 mm (3.4 in)
1932
58.4 mm (2.3 in)
1933
106.9 mm (4.2 in)
1934
41.9 mm (1.6 in)
1935
84.6 mm (3.3 in)
1936
71.9 mm (2.8 in)
1937
54.6 mm (2.1 in)
1938
78.0 mm (3.1 in)
1939
44.5 mm (1.8 in)
1940
86.4 mm (3.4 in)
1941
85.1 mm (3.4 in)
1942
41.9 mm (1.6 in)
1943
77.5 mm (3.1 in)
1944
97.0 mm (3.8 in)
1945
45.5 mm (1.8 in)
1946
83.1 mm (3.3 in)
1947
70.9 mm (2.8 in)
1948
44.2 mm (1.7 in)
1949
109.7 mm (4.3 in)
1950
11.4 mm (0.4 in)
Wettest five days (Rx5day)
The wettest five days of the year at Afton, 1894 to 1950. The record is 263.4 mm (10.4 in) in 1903, marked on the chart; the median year is 106.2 mm (4.2 in).
Wettest five days (Rx5day) at Afton by year
Year
Wettest five days (Rx5day)
1894
44.5 mm (1.8 in)
1895
129.1 mm (5.1 in)
1896
110.2 mm (4.3 in)
1897
165.0 mm (6.5 in)
1898
74.9 mm (2.9 in)
1899
93.4 mm (3.7 in)
1900
158.7 mm (6.2 in)
1901
93.2 mm (3.7 in)
1902
111.7 mm (4.4 in)
1903
263.4 mm (10.4 in)
1904
76.3 mm (3.0 in)
1905
85.1 mm (3.4 in)
1906
68.1 mm (2.7 in)
1907
78.0 mm (3.1 in)
1908
152.1 mm (6.0 in)
1909
148.1 mm (5.8 in)
1910
127.5 mm (5.0 in)
1911
91.0 mm (3.6 in)
1912
108.2 mm (4.3 in)
1913
81.4 mm (3.2 in)
1914
198.5 mm (7.8 in)
1915
259.8 mm (10.2 in)
1916
83.6 mm (3.3 in)
1917
150.1 mm (5.9 in)
1918
70.9 mm (2.8 in)
1919
156.2 mm (6.1 in)
1920
120.8 mm (4.8 in)
1921
143.0 mm (5.6 in)
1922
123.0 mm (4.8 in)
1923
77.7 mm (3.1 in)
1924
133.3 mm (5.2 in)
1925
77.0 mm (3.0 in)
1926
114.4 mm (4.5 in)
1927
104.6 mm (4.1 in)
1928
105.4 mm (4.1 in)
1929
62.3 mm (2.5 in)
1930
106.2 mm (4.2 in)
1931
101.8 mm (4.0 in)
1932
136.5 mm (5.4 in)
1933
114.8 mm (4.5 in)
1934
93.9 mm (3.7 in)
1935
113.6 mm (4.5 in)
1936
77.5 mm (3.1 in)
1937
67.8 mm (2.7 in)
1938
118.4 mm (4.7 in)
1939
91.5 mm (3.6 in)
1940
167.6 mm (6.6 in)
1941
121.4 mm (4.8 in)
1942
66.9 mm (2.6 in)
1943
118.6 mm (4.7 in)
1944
111.5 mm (4.4 in)
1945
76.8 mm (3.0 in)
1946
84.1 mm (3.3 in)
1947
84.3 mm (3.3 in)
1948
61.8 mm (2.4 in)
1949
149.3 mm (5.9 in)
1950
11.4 mm (0.4 in)
Longest dry spell (CDD)
The longest dry spell of the year at Afton, 1894 to 1950. The record is 52 days in 1904, marked on the chart; the median year is 27 days.
Longest dry spell (CDD) at Afton by year
Year
Longest dry spell (CDD)
1894
33 days
1895
31 days
1896
34 days
1897
23 days
1898
22 days
1899
31 days
1900
29 days
1901
29 days
1902
20 days
1903
33 days
1904
52 days
1905
26 days
1906
40 days
1907
25 days
1908
25 days
1909
25 days
1910
41 days
1911
29 days
1912
26 days
1913
27 days
1914
46 days
1915
26 days
1916
26 days
1917
34 days
1918
33 days
1919
31 days
1920
26 days
1921
34 days
1922
25 days
1923
18 days
1924
22 days
1925
36 days
1926
16 days
1927
22 days
1928
17 days
1929
21 days
1930
29 days
1931
34 days
1932
24 days
1933
32 days
1934
35 days
1935
18 days
1936
24 days
1937
27 days
1938
25 days
1939
37 days
1940
25 days
1941
18 days
1942
31 days
1943
20 days
1944
24 days
1945
24 days
1946
33 days
1947
35 days
1948
21 days
1949
27 days
1950
28 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
38 years with a frost
Across 38 years with a frost, the median last spring frost at Afton falls on 27 April and the median first autumn frost on 10 October, which leaves a median of 163 days between them.
Fitted over all years, the growing season changes by +2.0 days per decade at this station.
Frost dates and growing season at Afton
Measure
Median, all years
Earliest period
Recent period (1906 to 1948)
Recent against earliest
Fitted trend
Last spring frost
27 April
n/a
29 April
n/a
+0.4 days per decade
First autumn frost
10 October
n/a
11 October
n/a
+2.4 days per decade
Growing days
163 days
n/a
162 days
n/a
+2.0 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
48 years, 1895 to 1949
A day with at least 65.8 mm (2.6 in) of rain is expected about once in 2 years. A day with at least 183.9 mm (7.2 in) of rain is expected about once in 100 years.
Rainfall return levels at Afton: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
65.8 mm (2.6 in)
5 years
90.5 mm (3.6 in)
10 years
109.3 mm (4.3 in)
25 years
136.3 mm (5.4 in)
50 years
158.9 mm (6.3 in)
Longer than the 48 years of record
100 years
183.9 mm (7.2 in)
Longer than the 48 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, 48 years of values from 1895 to 1949.
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: 236.2 mm (9.3 in) in 1903; 112.0 mm (4.4 in) in 1922; 111.8 mm (4.4 in) in 1895.
Download the Data
Data for Afton standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Afton 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.