Record envelope, standing records and threshold days for Mason City (USC00255250), Nebraska, United States, with 124 years of record.
Key Facts for Mason City
Mason City (USC00255250) is a weather station in Nebraska, United States at 41.22 latitude and -99.29 longitude, 699 m (2,292 ft) above sea level.
The station reports from 1893 to 2016, 124 years of record.
1,464 records set at Mason City still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Mason City set a daily record high minimum temperature of 19.4 C (66.9 F) on 31 August 2016.
About the Station
Location: Nebraska, United States, 41.22 latitude, -99.29 longitude.
Elevation: 699 m (2,292 ft).
Period of record: 1893 to 2016, 124 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 Mason City. 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 Mason City, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
23.3 C (73.9 F)
-32.2 C (-26.0 F)
n/a
n/a
Feb
25.6 C (78.1 F)
-37.8 C (-36.0 F)
n/a
n/a
Mar
31.7 C (89.1 F)
-27.8 C (-18.0 F)
n/a
n/a
Apr
34.4 C (93.9 F)
-13.3 C (8.1 F)
n/a
n/a
May
37.8 C (100.0 F)
-6.7 C (19.9 F)
n/a
n/a
Jun
41.1 C (106.0 F)
-1.1 C (30.0 F)
n/a
n/a
Jul
42.2 C (108.0 F)
2.8 C (37.0 F)
n/a
n/a
Aug
40.6 C (105.1 F)
3.3 C (37.9 F)
n/a
n/a
Sep
38.9 C (102.0 F)
-6.1 C (21.0 F)
n/a
n/a
Oct
34.4 C (93.9 F)
-15.6 C (3.9 F)
n/a
n/a
Nov
28.9 C (84.0 F)
-25.0 C (-13.0 F)
n/a
n/a
Dec
22.2 C (72.0 F)
-33.3 C (-27.9 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Mason City still stand. 1989 holds the most, with 60.
Standing records at Mason City by the year they were set
Year set
Standing records
1893
39
1894
57
1895
44
1896
37
1897
34
1898
49
1899
47
1900
36
1901
33
1902
30
1903
26
1904
19
1905
24
1937
4
1986
3
1987
27
1988
45
1989
60
1990
40
1991
40
1992
27
1993
29
1994
34
1995
31
1996
36
1997
40
1998
35
1999
32
2000
36
2001
21
2002
42
2003
36
2004
24
2005
45
2006
39
2007
22
2008
12
2009
31
2010
17
2011
20
2012
27
2013
26
2014
36
2015
36
2016
36
All-Time Record Progression
3 new records
3 all-time records were set at Mason City between 30 June 1964 and 11 July 2016. Each dot is a new record.
When Mason City set new all-time records
Date
Kind
Detail
1964-06-30
Record daily precipitation
Record daily precipitation 190.5 mm (7.5 in)
2006-07-19
Record high maximum temperature
Record high maximum temperature 42.2 C (108.0 F)
2016-07-11
Record high minimum temperature
Record high minimum temperature 26.1 C (79.0 F)
Wettest Day of Each Month
Jun: 190.5 mm (7.5 in)
The wettest day on record for each calendar month at Mason City. The most was 190.5 mm (7.5 in) on 30 June 1964.
Record daily precipitation for each month at Mason City
Month
Record daily precipitation (mm)
Date
Jan
26.7 mm (1.1 in)
19 January 1988
Feb
43.2 mm (1.7 in)
19 February 1971
Mar
78.7 mm (3.1 in)
17 March 1987
Apr
158.2 mm (6.2 in)
20 April 1905
May
99.1 mm (3.9 in)
24 May 2008
Jun
190.5 mm (7.5 in)
30 June 1964
Jul
94.5 mm (3.7 in)
20 July 1973
Aug
91.4 mm (3.6 in)
5 August 2010
Sep
108.0 mm (4.3 in)
3 September 1942
Oct
87.9 mm (3.5 in)
5 October 1946
Nov
45.7 mm (1.8 in)
20 November 1975
Dec
40.6 mm (1.6 in)
5 December 1913
Period of Record Coverage
1893 to 2016
Complete yearUnder 90 percent of days
45 years of record at Mason City, 1893 to 2016. 10 years have data for under 90 percent of days and are left out of rankings: 1893, 1894, 1895, 1905, 1937, 1986, 2010, 2011 and others.
Cooler than the station meanWarmer than the station mean
One stripe for each of 31 complete years at Mason City, 1896 to 2015. Blue stripes are years cooler than the station's own mean of 9.3 C (48.8 F); red stripes are warmer. The coolest year was 1993, at 7.5 C (45.5 F), and the warmest was 2006, at 10.7 C (51.2 F). The strongest colour marks a difference of 1.9 C (3.4 F).
Annual mean temperature at Mason City as warming stripes, 1896 to 2015
Year
Annual mean temperature
Difference from the station mean
1896
9.4 C
+0.10 C
1897
9.2 C
-0.16 C
1898
9.0 C
-0.38 C
1899
8.6 C
-0.77 C
1900
10.3 C
+0.99 C
1902
8.6 C
-0.69 C
1987
10.1 C
+0.80 C
1988
9.6 C
+0.25 C
1989
8.4 C
-0.95 C
1990
9.6 C
+0.31 C
1991
9.8 C
+0.45 C
1992
9.0 C
-0.33 C
1993
7.5 C
-1.81 C
1994
9.2 C
-0.17 C
1995
8.8 C
-0.52 C
1996
7.7 C
-1.67 C
1997
9.1 C
-0.20 C
1998
10.1 C
+0.74 C
1999
10.1 C
+0.81 C
2000
9.8 C
+0.48 C
2002
10.2 C
+0.84 C
2003
9.7 C
+0.32 C
2004
9.6 C
+0.23 C
2005
10.4 C
+1.08 C
2006
10.7 C
+1.33 C
2007
9.7 C
+0.40 C
2008
8.5 C
-0.83 C
2009
8.1 C
-1.27 C
2013
9.1 C
-0.27 C
2014
9.0 C
-0.34 C
2015
10.5 C
+1.13 C
The fitted trend in annual mean temperature here over 1896 to 2015 is 0.02 C (-0.05 to 0.10) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: 0.04 F (-0.09 to 0.17) per decade. The slope is a straight line fitted to 31 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Mason City
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.02 C (-0.05 to 0.10) per decade
0.04 F (-0.09 to 0.17) per decade
1896 to 2015
31
Not clearly different from zero
Mean daily maximum
-0.07 C (-0.16 to 0.03) per decade
-0.12 F (-0.29 to 0.05) per decade
1896 to 2015
31
Not clearly different from zero
Mean daily minimum
0.11 C (0.04 to 0.18) per decade
0.2 F (0.1 to 0.3) per decade
1896 to 2015
31
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
1893 to 2016
Yearly extremes at Mason City: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
42.2 C (108.0 F)
2006
38.3 C (100.9 F)
45
Coldest night (TNn)
-37.8 C (-36.0 F)
1899
-26.7 C (-16.1 F)
45
Wettest day (Rx1day)
190.5 mm (7.5 in)
1964
50.6 mm (2.0 in)
124
Wettest five days (Rx5day)
198.1 mm (7.8 in)
1964
76.6 mm (3.0 in)
124
Longest dry spell (CDD)
72 days
1972
34 days
124
Hottest day (TXx)
The hottest day of the year at Mason City, 1893 to 2016. The record is 42.2 C (108.0 F) in 2006, marked on the chart; the median year is 38.3 C (100.9 F).
Hottest day (TXx) at Mason City by year
Year
Hottest day (TXx)
1893
37.8 C (100.0 F)
1894
41.1 C (106.0 F)
1895
38.9 C (102.0 F)
1896
38.3 C (100.9 F)
1897
39.4 C (102.9 F)
1898
39.4 C (102.9 F)
1899
40.6 C (105.1 F)
1900
41.1 C (106.0 F)
1901
40.6 C (105.1 F)
1902
37.8 C (100.0 F)
1903
37.2 C (99.0 F)
1904
36.1 C (97.0 F)
1905
35.6 C (96.1 F)
1906
n/a
1907
n/a
1908
n/a
1909
n/a
1910
n/a
1911
n/a
1912
n/a
1913
n/a
1914
n/a
1915
n/a
1916
n/a
1917
n/a
1918
n/a
1919
n/a
1920
n/a
1921
n/a
1922
n/a
1923
n/a
1924
n/a
1925
n/a
1926
n/a
1927
n/a
1928
n/a
1929
n/a
1930
n/a
1931
n/a
1932
n/a
1933
n/a
1934
n/a
1935
n/a
1936
n/a
1937
19.4 C (66.9 F)
1938
n/a
1939
n/a
1940
n/a
1941
n/a
1942
n/a
1943
n/a
1944
n/a
1945
n/a
1946
n/a
1947
n/a
1948
n/a
1949
n/a
1950
n/a
1951
n/a
1952
n/a
1953
n/a
1954
n/a
1955
n/a
1956
n/a
1957
n/a
1958
n/a
1959
n/a
1960
n/a
1961
n/a
1962
n/a
1963
n/a
1964
n/a
1965
n/a
1966
n/a
1967
n/a
1968
n/a
1969
n/a
1970
n/a
1971
n/a
1972
n/a
1973
n/a
1974
n/a
1975
n/a
1976
n/a
1977
n/a
1978
n/a
1979
n/a
1980
n/a
1981
n/a
1982
n/a
1983
n/a
1984
n/a
1985
n/a
1986
20.0 C (68.0 F)
1987
36.7 C (98.1 F)
1988
41.1 C (106.0 F)
1989
38.3 C (100.9 F)
1990
41.1 C (106.0 F)
1991
38.9 C (102.0 F)
1992
34.4 C (93.9 F)
1993
34.4 C (93.9 F)
1994
36.7 C (98.1 F)
1995
39.4 C (102.9 F)
1996
33.3 C (91.9 F)
1997
38.3 C (100.9 F)
1998
38.9 C (102.0 F)
1999
36.7 C (98.1 F)
2000
39.4 C (102.9 F)
2001
40.6 C (105.1 F)
2002
40.6 C (105.1 F)
2003
40.0 C (104.0 F)
2004
36.7 C (98.1 F)
2005
40.0 C (104.0 F)
2006
42.2 C (108.0 F)
2007
36.1 C (97.0 F)
2008
38.9 C (102.0 F)
2009
36.1 C (97.0 F)
2010
35.6 C (96.1 F)
2011
38.3 C (100.9 F)
2012
40.0 C (104.0 F)
2013
38.3 C (100.9 F)
2014
36.1 C (97.0 F)
2015
38.3 C (100.9 F)
2016
39.4 C (102.9 F)
Coldest night (TNn)
The coldest night of the year at Mason City, 1893 to 2016. The record is -37.8 C (-36.0 F) in 1899, marked on the chart; the median year is -26.7 C (-16.1 F).
Coldest night (TNn) at Mason City by year
Year
Coldest night (TNn)
1893
-33.3 C (-27.9 F)
1894
-28.3 C (-18.9 F)
1895
-31.1 C (-24.0 F)
1896
-25.6 C (-14.1 F)
1897
-26.1 C (-15.0 F)
1898
-27.2 C (-17.0 F)
1899
-37.8 C (-36.0 F)
1900
-30.6 C (-23.1 F)
1901
-33.3 C (-27.9 F)
1902
-30.0 C (-22.0 F)
1903
-29.4 C (-20.9 F)
1904
-26.7 C (-16.1 F)
1905
-32.8 C (-27.0 F)
1906
n/a
1907
n/a
1908
n/a
1909
n/a
1910
n/a
1911
n/a
1912
n/a
1913
n/a
1914
n/a
1915
n/a
1916
n/a
1917
n/a
1918
n/a
1919
n/a
1920
n/a
1921
n/a
1922
n/a
1923
n/a
1924
n/a
1925
n/a
1926
n/a
1927
n/a
1928
n/a
1929
n/a
1930
n/a
1931
n/a
1932
n/a
1933
n/a
1934
n/a
1935
n/a
1936
n/a
1937
-22.8 C (-9.0 F)
1938
n/a
1939
n/a
1940
n/a
1941
n/a
1942
n/a
1943
n/a
1944
n/a
1945
n/a
1946
n/a
1947
n/a
1948
n/a
1949
n/a
1950
n/a
1951
n/a
1952
n/a
1953
n/a
1954
n/a
1955
n/a
1956
n/a
1957
n/a
1958
n/a
1959
n/a
1960
n/a
1961
n/a
1962
n/a
1963
n/a
1964
n/a
1965
n/a
1966
n/a
1967
n/a
1968
n/a
1969
n/a
1970
n/a
1971
n/a
1972
n/a
1973
n/a
1974
n/a
1975
n/a
1976
n/a
1977
n/a
1978
n/a
1979
n/a
1980
n/a
1981
n/a
1982
n/a
1983
n/a
1984
n/a
1985
n/a
1986
-23.9 C (-11.0 F)
1987
-20.6 C (-5.1 F)
1988
-32.2 C (-26.0 F)
1989
-32.2 C (-26.0 F)
1990
-27.2 C (-17.0 F)
1991
-25.0 C (-13.0 F)
1992
-19.4 C (-2.9 F)
1993
-27.8 C (-18.0 F)
1994
-32.8 C (-27.0 F)
1995
-25.6 C (-14.1 F)
1996
-31.7 C (-25.1 F)
1997
-27.2 C (-17.0 F)
1998
-26.1 C (-15.0 F)
1999
-26.7 C (-16.1 F)
2000
-22.8 C (-9.0 F)
2001
-24.4 C (-11.9 F)
2002
-23.9 C (-11.0 F)
2003
-27.2 C (-17.0 F)
2004
-25.6 C (-14.1 F)
2005
-27.2 C (-17.0 F)
2006
-24.4 C (-11.9 F)
2007
-26.1 C (-15.0 F)
2008
-26.7 C (-16.1 F)
2009
-24.4 C (-11.9 F)
2010
-31.1 C (-24.0 F)
2011
-21.7 C (-7.1 F)
2012
-21.7 C (-7.1 F)
2013
-23.3 C (-9.9 F)
2014
-28.3 C (-18.9 F)
2015
-26.1 C (-15.0 F)
2016
-22.8 C (-9.0 F)
Wettest day (Rx1day)
The wettest day of the year at Mason City, 1893 to 2016. The record is 190.5 mm (7.5 in) in 1964, marked on the chart; the median year is 50.6 mm (2.0 in).
Wettest day (Rx1day) at Mason City by year
Year
Wettest day (Rx1day)
1893
22.9 mm (0.9 in)
1894
40.6 mm (1.6 in)
1895
70.6 mm (2.8 in)
1896
61.0 mm (2.4 in)
1897
74.9 mm (2.9 in)
1898
45.2 mm (1.8 in)
1899
47.2 mm (1.9 in)
1900
63.5 mm (2.5 in)
1901
43.2 mm (1.7 in)
1902
50.8 mm (2.0 in)
1903
69.9 mm (2.8 in)
1904
49.8 mm (2.0 in)
1905
158.2 mm (6.2 in)
1906
66.0 mm (2.6 in)
1907
39.4 mm (1.6 in)
1908
63.5 mm (2.5 in)
1909
52.1 mm (2.1 in)
1910
62.2 mm (2.4 in)
1911
79.8 mm (3.1 in)
1912
38.1 mm (1.5 in)
1913
44.5 mm (1.8 in)
1914
43.2 mm (1.7 in)
1915
76.2 mm (3.0 in)
1916
29.2 mm (1.1 in)
1917
66.0 mm (2.6 in)
1918
43.2 mm (1.7 in)
1919
41.9 mm (1.6 in)
1920
30.5 mm (1.2 in)
1921
41.9 mm (1.6 in)
1922
6.4 mm (0.25 in)
1923
50.8 mm (2.0 in)
1924
58.4 mm (2.3 in)
1925
50.8 mm (2.0 in)
1926
67.3 mm (2.6 in)
1927
41.9 mm (1.6 in)
1928
48.3 mm (1.9 in)
1929
39.4 mm (1.6 in)
1930
61.0 mm (2.4 in)
1931
51.8 mm (2.0 in)
1932
40.6 mm (1.6 in)
1933
44.5 mm (1.8 in)
1934
27.9 mm (1.1 in)
1935
78.2 mm (3.1 in)
1936
48.3 mm (1.9 in)
1937
48.3 mm (1.9 in)
1938
45.7 mm (1.8 in)
1939
44.5 mm (1.8 in)
1940
40.6 mm (1.6 in)
1941
42.4 mm (1.7 in)
1942
108.0 mm (4.3 in)
1943
72.4 mm (2.9 in)
1944
45.7 mm (1.8 in)
1945
35.3 mm (1.4 in)
1946
87.9 mm (3.5 in)
1947
92.7 mm (3.6 in)
1948
62.2 mm (2.4 in)
1949
66.5 mm (2.6 in)
1950
77.7 mm (3.1 in)
1951
30.5 mm (1.2 in)
1952
27.9 mm (1.1 in)
1953
31.8 mm (1.3 in)
1954
53.3 mm (2.1 in)
1955
40.6 mm (1.6 in)
1956
39.4 mm (1.6 in)
1957
104.1 mm (4.1 in)
1958
38.1 mm (1.5 in)
1959
37.3 mm (1.5 in)
1960
53.3 mm (2.1 in)
1961
68.1 mm (2.7 in)
1962
49.5 mm (1.9 in)
1963
38.1 mm (1.5 in)
1964
190.5 mm (7.5 in)
1965
5.1 mm (0.20 in)
1966
39.6 mm (1.6 in)
1967
44.2 mm (1.7 in)
1968
58.2 mm (2.3 in)
1969
35.8 mm (1.4 in)
1970
40.6 mm (1.6 in)
1971
84.3 mm (3.3 in)
1972
55.9 mm (2.2 in)
1973
94.5 mm (3.7 in)
1974
60.2 mm (2.4 in)
1975
45.7 mm (1.8 in)
1976
52.1 mm (2.1 in)
1977
68.6 mm (2.7 in)
1978
54.9 mm (2.2 in)
1979
39.9 mm (1.6 in)
1980
37.1 mm (1.5 in)
1981
45.7 mm (1.8 in)
1982
62.2 mm (2.4 in)
1983
49.3 mm (1.9 in)
1984
88.9 mm (3.5 in)
1985
73.7 mm (2.9 in)
1986
46.0 mm (1.8 in)
1987
78.7 mm (3.1 in)
1988
42.4 mm (1.7 in)
1989
74.9 mm (2.9 in)
1990
79.2 mm (3.1 in)
1991
45.5 mm (1.8 in)
1992
59.2 mm (2.3 in)
1993
80.0 mm (3.1 in)
1994
41.4 mm (1.6 in)
1995
54.6 mm (2.1 in)
1996
53.8 mm (2.1 in)
1997
69.1 mm (2.7 in)
1998
49.5 mm (1.9 in)
1999
42.9 mm (1.7 in)
2000
44.7 mm (1.8 in)
2001
65.3 mm (2.6 in)
2002
30.5 mm (1.2 in)
2003
101.6 mm (4.0 in)
2004
75.2 mm (3.0 in)
2005
81.3 mm (3.2 in)
2006
90.9 mm (3.6 in)
2007
58.4 mm (2.3 in)
2008
99.1 mm (3.9 in)
2009
49.3 mm (1.9 in)
2010
91.4 mm (3.6 in)
2011
48.8 mm (1.9 in)
2012
50.3 mm (2.0 in)
2013
63.0 mm (2.5 in)
2014
49.3 mm (1.9 in)
2015
43.2 mm (1.7 in)
2016
76.2 mm (3.0 in)
Wettest five days (Rx5day)
The wettest five days of the year at Mason City, 1893 to 2016. The record is 198.1 mm (7.8 in) in 1964, marked on the chart; the median year is 76.6 mm (3.0 in).
Wettest five days (Rx5day) at Mason City by year
Year
Wettest five days (Rx5day)
1893
35.6 mm (1.4 in)
1894
45.7 mm (1.8 in)
1895
70.6 mm (2.8 in)
1896
61.0 mm (2.4 in)
1897
85.1 mm (3.4 in)
1898
60.2 mm (2.4 in)
1899
81.0 mm (3.2 in)
1900
63.5 mm (2.5 in)
1901
146.5 mm (5.8 in)
1902
70.3 mm (2.8 in)
1903
87.7 mm (3.5 in)
1904
90.7 mm (3.6 in)
1905
187.9 mm (7.4 in)
1906
125.7 mm (4.9 in)
1907
52.3 mm (2.1 in)
1908
63.5 mm (2.5 in)
1909
63.3 mm (2.5 in)
1910
124.4 mm (4.9 in)
1911
121.2 mm (4.8 in)
1912
65.7 mm (2.6 in)
1913
46.0 mm (1.8 in)
1914
94.0 mm (3.7 in)
1915
88.9 mm (3.5 in)
1916
29.2 mm (1.1 in)
1917
77.4 mm (3.0 in)
1918
45.7 mm (1.8 in)
1919
66.2 mm (2.6 in)
1920
54.6 mm (2.1 in)
1921
63.5 mm (2.5 in)
1922
7.6 mm (0.30 in)
1923
85.9 mm (3.4 in)
1924
74.1 mm (2.9 in)
1925
50.8 mm (2.0 in)
1926
124.4 mm (4.9 in)
1927
97.8 mm (3.9 in)
1928
52.1 mm (2.1 in)
1929
54.6 mm (2.1 in)
1930
75.8 mm (3.0 in)
1931
79.7 mm (3.1 in)
1932
59.7 mm (2.4 in)
1933
152.2 mm (6.0 in)
1934
39.3 mm (1.5 in)
1935
98.5 mm (3.9 in)
1936
75.0 mm (3.0 in)
1937
63.5 mm (2.5 in)
1938
59.7 mm (2.4 in)
1939
54.6 mm (2.1 in)
1940
74.9 mm (2.9 in)
1941
70.3 mm (2.8 in)
1942
108.0 mm (4.3 in)
1943
78.0 mm (3.1 in)
1944
67.8 mm (2.7 in)
1945
65.3 mm (2.6 in)
1946
176.5 mm (6.9 in)
1947
110.0 mm (4.3 in)
1948
83.0 mm (3.3 in)
1949
96.7 mm (3.8 in)
1950
79.0 mm (3.1 in)
1951
54.8 mm (2.2 in)
1952
34.3 mm (1.4 in)
1953
47.2 mm (1.9 in)
1954
71.4 mm (2.8 in)
1955
64.3 mm (2.5 in)
1956
58.5 mm (2.3 in)
1957
142.2 mm (5.6 in)
1958
69.4 mm (2.7 in)
1959
51.3 mm (2.0 in)
1960
110.7 mm (4.4 in)
1961
100.1 mm (3.9 in)
1962
80.0 mm (3.1 in)
1963
53.3 mm (2.1 in)
1964
198.1 mm (7.8 in)
1965
5.1 mm (0.20 in)
1966
59.4 mm (2.3 in)
1967
86.9 mm (3.4 in)
1968
111.8 mm (4.4 in)
1969
72.7 mm (2.9 in)
1970
69.8 mm (2.7 in)
1971
101.8 mm (4.0 in)
1972
68.1 mm (2.7 in)
1973
130.6 mm (5.1 in)
1974
86.1 mm (3.4 in)
1975
117.6 mm (4.6 in)
1976
58.0 mm (2.3 in)
1977
80.0 mm (3.1 in)
1978
102.1 mm (4.0 in)
1979
64.4 mm (2.5 in)
1980
65.8 mm (2.6 in)
1981
105.1 mm (4.1 in)
1982
66.5 mm (2.6 in)
1983
72.9 mm (2.9 in)
1984
108.7 mm (4.3 in)
1985
102.4 mm (4.0 in)
1986
58.7 mm (2.3 in)
1987
115.0 mm (4.5 in)
1988
52.8 mm (2.1 in)
1989
148.5 mm (5.8 in)
1990
101.8 mm (4.0 in)
1991
95.8 mm (3.8 in)
1992
88.2 mm (3.5 in)
1993
102.6 mm (4.0 in)
1994
66.3 mm (2.6 in)
1995
75.2 mm (3.0 in)
1996
91.7 mm (3.6 in)
1997
113.6 mm (4.5 in)
1998
81.0 mm (3.2 in)
1999
77.4 mm (3.0 in)
2000
50.8 mm (2.0 in)
2001
94.8 mm (3.7 in)
2002
44.0 mm (1.7 in)
2003
113.8 mm (4.5 in)
2004
93.0 mm (3.7 in)
2005
110.5 mm (4.4 in)
2006
121.4 mm (4.8 in)
2007
150.2 mm (5.9 in)
2008
154.2 mm (6.1 in)
2009
91.5 mm (3.6 in)
2010
95.5 mm (3.8 in)
2011
70.1 mm (2.8 in)
2012
59.4 mm (2.3 in)
2013
65.8 mm (2.6 in)
2014
118.1 mm (4.6 in)
2015
66.3 mm (2.6 in)
2016
108.5 mm (4.3 in)
Longest dry spell (CDD)
The longest dry spell of the year at Mason City, 1893 to 2016. The record is 72 days in 1972, marked on the chart; the median year is 34 days.
Longest dry spell (CDD) at Mason City by year
Year
Longest dry spell (CDD)
1893
32 days
1894
47 days
1895
25 days
1896
35 days
1897
35 days
1898
26 days
1899
26 days
1900
37 days
1901
31 days
1902
31 days
1903
31 days
1904
35 days
1905
34 days
1906
26 days
1907
32 days
1908
33 days
1909
31 days
1910
55 days
1911
39 days
1912
28 days
1913
32 days
1914
43 days
1915
25 days
1916
37 days
1917
35 days
1918
20 days
1919
31 days
1920
24 days
1921
47 days
1922
22 days
1923
54 days
1924
32 days
1925
21 days
1926
27 days
1927
29 days
1928
34 days
1929
18 days
1930
28 days
1931
40 days
1932
42 days
1933
31 days
1934
40 days
1935
24 days
1936
36 days
1937
26 days
1938
29 days
1939
55 days
1940
30 days
1941
16 days
1942
22 days
1943
38 days
1944
23 days
1945
39 days
1946
50 days
1947
34 days
1948
48 days
1949
32 days
1950
48 days
1951
45 days
1952
38 days
1953
43 days
1954
66 days
1955
38 days
1956
44 days
1957
42 days
1958
63 days
1959
31 days
1960
29 days
1961
25 days
1962
32 days
1963
34 days
1964
33 days
1965
18 days
1966
43 days
1967
59 days
1968
39 days
1969
26 days
1970
52 days
1971
27 days
1972
72 days
1973
38 days
1974
47 days
1975
32 days
1976
39 days
1977
35 days
1978
33 days
1979
39 days
1980
39 days
1981
31 days
1982
28 days
1983
22 days
1984
33 days
1985
21 days
1986
34 days
1987
35 days
1988
29 days
1989
50 days
1990
26 days
1991
28 days
1992
34 days
1993
22 days
1994
45 days
1995
24 days
1996
36 days
1997
25 days
1998
39 days
1999
45 days
2000
26 days
2001
39 days
2002
30 days
2003
38 days
2004
32 days
2005
42 days
2006
34 days
2007
43 days
2008
39 days
2009
22 days
2010
20 days
2011
10 days
2012
50 days
2013
44 days
2014
65 days
2015
39 days
2016
40 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
31 years with a frost
Across 31 years with a frost, the median last spring frost at Mason City falls on 9 May and the median first autumn frost on 28 September, which leaves a median of 147 days between them.
Fitted over all years, the growing season changes by +1.3 days per decade at this station.
Frost dates and growing season at Mason City
Measure
Median, all years
Earliest period
Recent period (1897 to 2015)
Recent against earliest
Fitted trend
Last spring frost
9 May
n/a
9 May
n/a
0.0 days per decade
First autumn frost
28 September
n/a
29 September
n/a
+1.3 days per decade
Growing days
147 days
n/a
148 days
n/a
+1.3 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
87 years, 1895 to 2015
A day with at least 55.3 mm (2.2 in) of rain is expected about once in 2 years. A day with at least 129.3 mm (5.1 in) of rain is expected about once in 100 years.
Rainfall return levels at Mason City: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
55.3 mm (2.2 in)
5 years
73.9 mm (2.9 in)
10 years
86.6 mm (3.4 in)
25 years
103.4 mm (4.1 in)
50 years
116.2 mm (4.6 in)
100 years
129.3 mm (5.1 in)
Longer than the 87 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, 87 years of values from 1895 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: 158.2 mm (6.2 in) in 1905; 104.1 mm (4.1 in) in 1957; 101.6 mm (4.0 in) in 2003.
Download the Data
Data for Mason City standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Mason City 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 2026-10-16 (16 October 2026). Records are computed by this site and are not official.