Record envelope, standing records and threshold days for Ionia 2SSW (USC00204078), Michigan, United States, with 118 years of record.
Key Facts for Ionia 2SSW
Ionia 2SSW (USC00204078) is a weather station in Michigan, United States at 42.95 latitude and -85.08 longitude, 245 m (805 ft) above sea level.
The station reports from 1896 to 2013, 118 years of record.
1,464 records set at Ionia 2SSW still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Ionia 2SSW set a daily record high minimum temperature of 22.2 C (72.0 F) on 11 September 2013.
About the Station
Location: Michigan, United States, 42.95 latitude, -85.08 longitude.
Elevation: 245 m (805 ft).
Period of record: 1896 to 2013, 118 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 Ionia 2SSW. 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 Ionia 2SSW, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
18.3 C (64.9 F)
-31.7 C (-25.1 F)
n/a
n/a
Feb
20.6 C (69.1 F)
-31.7 C (-25.1 F)
n/a
n/a
Mar
30.0 C (86.0 F)
-26.1 C (-15.0 F)
n/a
n/a
Apr
31.1 C (88.0 F)
-14.4 C (6.1 F)
n/a
n/a
May
35.0 C (95.0 F)
-7.2 C (19.0 F)
n/a
n/a
Jun
38.9 C (102.0 F)
-1.7 C (28.9 F)
n/a
n/a
Jul
39.4 C (102.9 F)
2.8 C (37.0 F)
n/a
n/a
Aug
39.4 C (102.9 F)
2.2 C (36.0 F)
n/a
n/a
Sep
36.7 C (98.1 F)
-3.9 C (25.0 F)
n/a
n/a
Oct
31.7 C (89.1 F)
-8.9 C (16.0 F)
n/a
n/a
Nov
26.1 C (79.0 F)
-21.7 C (-7.1 F)
n/a
n/a
Dec
20.0 C (68.0 F)
-25.6 C (-14.1 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Ionia 2SSW still stand. 1965 holds the most, with 45.
Standing records at Ionia 2SSW by the year they were set
Year set
Standing records
1896
10
1897
30
1898
22
1899
38
1900
30
1901
18
1902
14
1903
6
1904
19
1939
11
1942
1
1943
18
1945
26
1946
26
1947
29
1948
15
1949
25
1950
25
1951
19
1952
17
1953
18
1954
12
1955
13
1956
12
1957
13
1958
22
1959
26
1960
20
1961
10
1962
27
1963
39
1964
20
1965
45
1966
19
1967
14
1968
16
1969
14
1970
15
1971
15
1972
16
1973
24
1974
11
1975
18
1976
28
1977
32
1978
3
1979
5
1981
3
1982
29
1983
19
1984
23
1985
13
1986
19
1987
17
1988
35
1989
23
1990
19
1991
13
1992
14
1993
18
1994
14
1995
17
1996
20
1997
12
1998
12
1999
17
2000
33
2001
19
2002
21
2003
9
2004
14
2005
8
2006
20
2007
14
2008
12
2009
9
2010
11
2011
13
2012
29
2013
9
All-Time Record Progression
6 new records
6 all-time records were set at Ionia 2SSW between 15 January 1972 and 19 January 1994. Each dot is a new record.
When Ionia 2SSW set new all-time records
Date
Kind
Detail
1972-01-15
Record low maximum temperature
Record low maximum temperature -19.4 C (-2.9 F)
1978-01-26
Record snow depth
Record snow depth 55.9 cm (22.0 in)
1978-01-27
Record snow depth
Record snow depth 61.0 cm (24.0 in)
1979-01-16
Record snow depth
Record snow depth 66.0 cm (26.0 in)
1981-10-01
Record daily precipitation
Record daily precipitation 130.0 mm (5.1 in)
1994-01-19
Record low maximum temperature
Record low maximum temperature -20.6 C (-5.1 F)
Wettest Day of Each Month
Oct: 130.0 mm (5.1 in)
The wettest day on record for each calendar month at Ionia 2SSW. The most was 130.0 mm (5.1 in) on 1 October 1981.
Record daily precipitation for each month at Ionia 2SSW
Month
Record daily precipitation (mm)
Date
Jan
35.6 mm (1.4 in)
27 January 1967
Feb
77.5 mm (3.1 in)
22 February 1990
Mar
56.1 mm (2.2 in)
3 March 1985
Apr
66.0 mm (2.6 in)
23 April 1999
May
65.3 mm (2.6 in)
21 May 1996
Jun
94.5 mm (3.7 in)
24 June 1994
Jul
86.4 mm (3.4 in)
28 July 1945
Aug
104.1 mm (4.1 in)
21 August 1958
Sep
120.9 mm (4.8 in)
10 September 1986
Oct
130.0 mm (5.1 in)
1 October 1981
Nov
55.4 mm (2.2 in)
11 November 1995
Dec
61.0 mm (2.4 in)
10 December 1971
Period of Record Coverage
1896 to 2013
Complete yearUnder 90 percent of days
80 years of record at Ionia 2SSW, 1896 to 2013. 18 years have data for under 90 percent of days and are left out of rankings: 1896, 1898, 1902, 1903, 1904, 1939, 1942, 1952 and others.
Cooler than the station meanWarmer than the station mean
One stripe for each of 60 complete years at Ionia 2SSW, 1897 to 2012. Blue stripes are years cooler than the station's own mean of 8.6 C (47.4 F); red stripes are warmer. The coolest year was 1989, at 6.8 C (44.2 F), and the warmest was 1998, at 10.4 C (50.7 F). The strongest colour marks a difference of 1.9 C (3.4 F).
Annual mean temperature at Ionia 2SSW as warming stripes, 1897 to 2012
Year
Annual mean temperature
Difference from the station mean
1897
8.3 C
-0.25 C
1900
9.2 C
+0.66 C
1901
8.4 C
-0.14 C
1945
8.8 C
+0.19 C
1946
9.7 C
+1.17 C
1947
8.7 C
+0.14 C
1948
9.4 C
+0.78 C
1949
10.3 C
+1.74 C
1950
8.7 C
+0.15 C
1951
8.7 C
+0.13 C
1955
10.0 C
+1.45 C
1956
9.2 C
+0.60 C
1957
9.4 C
+0.84 C
1959
8.7 C
+0.15 C
1961
8.7 C
+0.09 C
1962
7.6 C
-0.97 C
1963
7.8 C
-0.80 C
1965
8.2 C
-0.40 C
1966
8.0 C
-0.55 C
1967
8.0 C
-0.61 C
1968
8.7 C
+0.10 C
1969
8.3 C
-0.30 C
1970
8.4 C
-0.20 C
1971
8.8 C
+0.26 C
1972
7.6 C
-0.96 C
1973
10.2 C
+1.60 C
1974
8.9 C
+0.36 C
1975
9.4 C
+0.87 C
1976
8.4 C
-0.16 C
1977
9.3 C
+0.68 C
1978
8.2 C
-0.40 C
1982
7.9 C
-0.66 C
1983
8.2 C
-0.34 C
1984
7.7 C
-0.86 C
1985
7.6 C
-1.02 C
1986
8.3 C
-0.28 C
1987
9.7 C
+1.10 C
1988
8.3 C
-0.28 C
1989
6.8 C
-1.78 C
1992
7.6 C
-0.93 C
1993
7.5 C
-1.07 C
1994
7.8 C
-0.73 C
1995
8.0 C
-0.58 C
1996
7.2 C
-1.36 C
1997
7.7 C
-0.90 C
1998
10.4 C
+1.81 C
1999
9.1 C
+0.51 C
2000
8.3 C
-0.26 C
2001
9.3 C
+0.77 C
2002
8.9 C
+0.35 C
2003
7.8 C
-0.77 C
2004
8.1 C
-0.48 C
2005
8.8 C
+0.19 C
2006
9.4 C
+0.81 C
2007
8.8 C
+0.25 C
2008
7.8 C
-0.78 C
2009
7.7 C
-0.86 C
2010
9.2 C
+0.61 C
2011
8.5 C
-0.06 C
2012
10.2 C
+1.58 C
The fitted trend in annual mean temperature here over 1897 to 2012 is -0.05 C (-0.13 to 0.03) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: -0.1 F (-0.2 to 0.1) per decade. The slope is a straight line fitted to 60 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Ionia 2SSW
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
-0.05 C (-0.13 to 0.03) per decade
-0.1 F (-0.2 to 0.1) per decade
1897 to 2012
60
Not clearly different from zero
Mean daily maximum
-0.2 C (-0.3 to -0.1) per decade
-0.3 F (-0.5 to -0.1) per decade
1897 to 2012
60
Fall
Mean daily minimum
0.07 C (-0.03 to 0.16) per decade
0.12 F (-0.05 to 0.29) per decade
1897 to 2012
60
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
1896 to 2013
Yearly extremes at Ionia 2SSW: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
39.4 C (102.9 F)
1947
34.4 C (93.9 F)
80
Coldest night (TNn)
-31.7 C (-25.1 F)
1899
-23.3 C (-9.9 F)
80
Wettest day (Rx1day)
130.0 mm (5.1 in)
1981
55.5 mm (2.2 in)
80
Wettest five days (Rx5day)
182.1 mm (7.2 in)
1987
80.2 mm (3.2 in)
80
Longest dry spell (CDD)
41 days
1899
20 days
80
Hottest day (TXx)
The hottest day of the year at Ionia 2SSW, 1896 to 2013. The record is 39.4 C (102.9 F) in 1947, marked on the chart; the median year is 34.4 C (93.9 F).
Hottest day (TXx) at Ionia 2SSW by year
Year
Hottest day (TXx)
1896
30.6 C (87.1 F)
1897
38.9 C (102.0 F)
1898
37.2 C (99.0 F)
1899
36.1 C (97.0 F)
1900
37.2 C (99.0 F)
1901
36.7 C (98.1 F)
1902
33.3 C (91.9 F)
1903
35.0 C (95.0 F)
1904
30.6 C (87.1 F)
1939
35.6 C (96.1 F)
1942
27.2 C (81.0 F)
1943
35.0 C (95.0 F)
1945
35.6 C (96.1 F)
1946
35.0 C (95.0 F)
1947
39.4 C (102.9 F)
1948
36.7 C (98.1 F)
1949
36.7 C (98.1 F)
1950
36.1 C (97.0 F)
1951
33.3 C (91.9 F)
1952
37.2 C (99.0 F)
1953
38.9 C (102.0 F)
1954
34.4 C (93.9 F)
1955
37.8 C (100.0 F)
1956
34.4 C (93.9 F)
1957
34.4 C (93.9 F)
1958
33.9 C (93.0 F)
1959
35.0 C (95.0 F)
1960
35.0 C (95.0 F)
1961
33.3 C (91.9 F)
1962
33.3 C (91.9 F)
1963
36.1 C (97.0 F)
1964
37.8 C (100.0 F)
1965
34.4 C (93.9 F)
1966
35.6 C (96.1 F)
1967
31.7 C (89.1 F)
1968
33.9 C (93.0 F)
1969
33.9 C (93.0 F)
1970
34.4 C (93.9 F)
1971
36.1 C (97.0 F)
1972
33.3 C (91.9 F)
1973
36.1 C (97.0 F)
1974
35.6 C (96.1 F)
1975
36.7 C (98.1 F)
1976
34.4 C (93.9 F)
1977
36.7 C (98.1 F)
1978
34.4 C (93.9 F)
1979
31.7 C (89.1 F)
1981
31.1 C (88.0 F)
1982
32.2 C (90.0 F)
1983
37.8 C (100.0 F)
1984
35.0 C (95.0 F)
1985
34.4 C (93.9 F)
1986
33.9 C (93.0 F)
1987
37.2 C (99.0 F)
1988
39.4 C (102.9 F)
1989
33.9 C (93.0 F)
1990
34.4 C (93.9 F)
1991
33.9 C (93.0 F)
1992
35.0 C (95.0 F)
1993
33.3 C (91.9 F)
1994
33.9 C (93.0 F)
1995
36.7 C (98.1 F)
1996
35.6 C (96.1 F)
1997
34.4 C (93.9 F)
1998
34.4 C (93.9 F)
1999
35.6 C (96.1 F)
2000
32.2 C (90.0 F)
2001
35.0 C (95.0 F)
2002
32.8 C (91.0 F)
2003
33.9 C (93.0 F)
2004
31.7 C (89.1 F)
2005
34.4 C (93.9 F)
2006
34.4 C (93.9 F)
2007
34.4 C (93.9 F)
2008
32.8 C (91.0 F)
2009
32.8 C (91.0 F)
2010
32.8 C (91.0 F)
2011
35.0 C (95.0 F)
2012
37.2 C (99.0 F)
2013
33.9 C (93.0 F)
Coldest night (TNn)
The coldest night of the year at Ionia 2SSW, 1896 to 2013. The record is -31.7 C (-25.1 F) in 1899, marked on the chart; the median year is -23.3 C (-9.9 F).
Coldest night (TNn) at Ionia 2SSW by year
Year
Coldest night (TNn)
1896
-25.6 C (-14.1 F)
1897
-25.0 C (-13.0 F)
1898
-20.0 C (-4.0 F)
1899
-31.7 C (-25.1 F)
1900
-24.4 C (-11.9 F)
1901
-25.0 C (-13.0 F)
1902
-21.7 C (-7.1 F)
1903
-24.4 C (-11.9 F)
1904
-31.1 C (-24.0 F)
1939
-13.9 C (7.0 F)
1942
-21.7 C (-7.1 F)
1943
-26.1 C (-15.0 F)
1945
-22.2 C (-8.0 F)
1946
-20.0 C (-4.0 F)
1947
-26.1 C (-15.0 F)
1948
-24.4 C (-11.9 F)
1949
-17.8 C (0.0 F)
1950
-22.2 C (-8.0 F)
1951
-27.8 C (-18.0 F)
1952
-15.6 C (3.9 F)
1953
-16.7 C (1.9 F)
1954
-20.0 C (-4.0 F)
1955
-22.2 C (-8.0 F)
1956
-22.8 C (-9.0 F)
1957
-21.1 C (-6.0 F)
1958
-22.2 C (-8.0 F)
1959
-29.4 C (-20.9 F)
1960
-23.3 C (-9.9 F)
1961
-27.2 C (-17.0 F)
1962
-28.3 C (-18.9 F)
1963
-31.7 C (-25.1 F)
1964
-27.8 C (-18.0 F)
1965
-26.7 C (-16.1 F)
1966
-27.2 C (-17.0 F)
1967
-27.8 C (-18.0 F)
1968
-23.9 C (-11.0 F)
1969
-23.3 C (-9.9 F)
1970
-23.3 C (-9.9 F)
1971
-25.6 C (-14.1 F)
1972
-27.2 C (-17.0 F)
1973
-27.2 C (-17.0 F)
1974
-24.4 C (-11.9 F)
1975
-19.4 C (-2.9 F)
1976
-25.6 C (-14.1 F)
1977
-25.6 C (-14.1 F)
1978
-24.4 C (-11.9 F)
1979
-27.2 C (-17.0 F)
1981
-13.3 C (8.1 F)
1982
-25.0 C (-13.0 F)
1983
-24.4 C (-11.9 F)
1984
-28.3 C (-18.9 F)
1985
-25.0 C (-13.0 F)
1986
-23.3 C (-9.9 F)
1987
-22.8 C (-9.0 F)
1988
-23.9 C (-11.0 F)
1989
-24.4 C (-11.9 F)
1990
-17.8 C (0.0 F)
1991
-16.7 C (1.9 F)
1992
-18.3 C (-0.9 F)
1993
-25.0 C (-13.0 F)
1994
-29.4 C (-20.9 F)
1995
-20.0 C (-4.0 F)
1996
-27.8 C (-18.0 F)
1997
-22.8 C (-9.0 F)
1998
-17.8 C (0.0 F)
1999
-20.6 C (-5.1 F)
2000
-23.9 C (-11.0 F)
2001
-18.9 C (-2.0 F)
2002
-18.9 C (-2.0 F)
2003
-23.3 C (-9.9 F)
2004
-22.2 C (-8.0 F)
2005
-23.3 C (-9.9 F)
2006
-18.9 C (-2.0 F)
2007
-23.3 C (-9.9 F)
2008
-21.7 C (-7.1 F)
2009
-23.3 C (-9.9 F)
2010
-17.8 C (0.0 F)
2011
-23.9 C (-11.0 F)
2012
-17.8 C (0.0 F)
2013
-20.6 C (-5.1 F)
Wettest day (Rx1day)
The wettest day of the year at Ionia 2SSW, 1896 to 2013. The record is 130.0 mm (5.1 in) in 1981, marked on the chart; the median year is 55.5 mm (2.2 in).
Wettest day (Rx1day) at Ionia 2SSW by year
Year
Wettest day (Rx1day)
1896
43.7 mm (1.7 in)
1897
59.7 mm (2.4 in)
1898
54.4 mm (2.1 in)
1899
25.4 mm (1.0 in)
1900
76.2 mm (3.0 in)
1901
50.8 mm (2.0 in)
1902
58.4 mm (2.3 in)
1903
38.1 mm (1.5 in)
1904
0.0 mm (0.00 in)
1939
87.6 mm (3.4 in)
1942
34.8 mm (1.4 in)
1943
41.4 mm (1.6 in)
1945
86.4 mm (3.4 in)
1946
37.3 mm (1.5 in)
1947
66.0 mm (2.6 in)
1948
55.9 mm (2.2 in)
1949
73.7 mm (2.9 in)
1950
61.0 mm (2.4 in)
1951
40.9 mm (1.6 in)
1952
46.5 mm (1.8 in)
1953
30.5 mm (1.2 in)
1954
78.7 mm (3.1 in)
1955
48.8 mm (1.9 in)
1956
57.2 mm (2.3 in)
1957
68.6 mm (2.7 in)
1958
104.1 mm (4.1 in)
1959
54.6 mm (2.1 in)
1960
44.7 mm (1.8 in)
1961
43.2 mm (1.7 in)
1962
40.6 mm (1.6 in)
1963
34.3 mm (1.4 in)
1964
50.3 mm (2.0 in)
1965
76.7 mm (3.0 in)
1966
39.9 mm (1.6 in)
1967
35.6 mm (1.4 in)
1968
32.0 mm (1.3 in)
1969
51.3 mm (2.0 in)
1970
57.7 mm (2.3 in)
1971
61.0 mm (2.4 in)
1972
84.1 mm (3.3 in)
1973
34.3 mm (1.4 in)
1974
35.3 mm (1.4 in)
1975
72.1 mm (2.8 in)
1976
57.4 mm (2.3 in)
1977
51.3 mm (2.0 in)
1978
62.0 mm (2.4 in)
1979
64.0 mm (2.5 in)
1981
130.0 mm (5.1 in)
1982
67.1 mm (2.6 in)
1983
50.5 mm (2.0 in)
1984
38.9 mm (1.5 in)
1985
90.4 mm (3.6 in)
1986
120.9 mm (4.8 in)
1987
70.4 mm (2.8 in)
1988
79.0 mm (3.1 in)
1989
52.1 mm (2.1 in)
1990
77.5 mm (3.1 in)
1991
38.1 mm (1.5 in)
1992
56.6 mm (2.2 in)
1993
63.2 mm (2.5 in)
1994
94.5 mm (3.7 in)
1995
55.4 mm (2.2 in)
1996
65.3 mm (2.6 in)
1997
51.1 mm (2.0 in)
1998
38.9 mm (1.5 in)
1999
66.0 mm (2.6 in)
2000
81.3 mm (3.2 in)
2001
41.7 mm (1.6 in)
2002
39.6 mm (1.6 in)
2003
44.5 mm (1.8 in)
2004
42.2 mm (1.7 in)
2005
27.4 mm (1.1 in)
2006
55.6 mm (2.2 in)
2007
33.3 mm (1.3 in)
2008
62.0 mm (2.4 in)
2009
48.8 mm (1.9 in)
2010
59.4 mm (2.3 in)
2011
76.2 mm (3.0 in)
2012
60.7 mm (2.4 in)
2013
64.5 mm (2.5 in)
Wettest five days (Rx5day)
The wettest five days of the year at Ionia 2SSW, 1896 to 2013. The record is 182.1 mm (7.2 in) in 1987, marked on the chart; the median year is 80.2 mm (3.2 in).
Wettest five days (Rx5day) at Ionia 2SSW by year
Year
Wettest five days (Rx5day)
1896
38.1 mm (1.5 in)
1897
74.9 mm (2.9 in)
1898
56.3 mm (2.2 in)
1899
42.4 mm (1.7 in)
1900
102.9 mm (4.1 in)
1901
91.4 mm (3.6 in)
1902
109.2 mm (4.3 in)
1903
63.5 mm (2.5 in)
1904
0.0 mm (0.00 in)
1939
89.4 mm (3.5 in)
1942
54.9 mm (2.2 in)
1943
49.0 mm (1.9 in)
1945
97.6 mm (3.8 in)
1946
61.9 mm (2.4 in)
1947
71.7 mm (2.8 in)
1948
72.4 mm (2.9 in)
1949
82.5 mm (3.2 in)
1950
132.4 mm (5.2 in)
1951
70.6 mm (2.8 in)
1952
63.0 mm (2.5 in)
1953
39.4 mm (1.6 in)
1954
87.1 mm (3.4 in)
1955
78.0 mm (3.1 in)
1956
81.9 mm (3.2 in)
1957
79.0 mm (3.1 in)
1958
131.5 mm (5.2 in)
1959
81.7 mm (3.2 in)
1960
55.9 mm (2.2 in)
1961
49.5 mm (1.9 in)
1962
117.8 mm (4.6 in)
1963
39.6 mm (1.6 in)
1964
71.6 mm (2.8 in)
1965
118.1 mm (4.6 in)
1966
70.6 mm (2.8 in)
1967
64.8 mm (2.6 in)
1968
102.7 mm (4.0 in)
1969
77.2 mm (3.0 in)
1970
75.1 mm (3.0 in)
1971
77.5 mm (3.1 in)
1972
96.8 mm (3.8 in)
1973
72.6 mm (2.9 in)
1974
64.5 mm (2.5 in)
1975
115.3 mm (4.5 in)
1976
76.0 mm (3.0 in)
1977
74.1 mm (2.9 in)
1978
62.5 mm (2.5 in)
1979
80.8 mm (3.2 in)
1981
174.7 mm (6.9 in)
1982
106.2 mm (4.2 in)
1983
87.6 mm (3.4 in)
1984
57.2 mm (2.3 in)
1985
126.2 mm (5.0 in)
1986
165.8 mm (6.5 in)
1987
182.1 mm (7.2 in)
1988
129.2 mm (5.1 in)
1989
95.0 mm (3.7 in)
1990
91.7 mm (3.6 in)
1991
63.0 mm (2.5 in)
1992
92.2 mm (3.6 in)
1993
85.8 mm (3.4 in)
1994
141.6 mm (5.6 in)
1995
61.5 mm (2.4 in)
1996
75.7 mm (3.0 in)
1997
92.3 mm (3.6 in)
1998
63.5 mm (2.5 in)
1999
89.4 mm (3.5 in)
2000
92.0 mm (3.6 in)
2001
79.5 mm (3.1 in)
2002
51.8 mm (2.0 in)
2003
118.7 mm (4.7 in)
2004
72.2 mm (2.8 in)
2005
57.1 mm (2.2 in)
2006
71.6 mm (2.8 in)
2007
112.5 mm (4.4 in)
2008
107.2 mm (4.2 in)
2009
81.3 mm (3.2 in)
2010
81.8 mm (3.2 in)
2011
102.1 mm (4.0 in)
2012
100.5 mm (4.0 in)
2013
107.9 mm (4.2 in)
Longest dry spell (CDD)
The longest dry spell of the year at Ionia 2SSW, 1896 to 2013. The record is 41 days in 1899, marked on the chart; the median year is 20 days.
Longest dry spell (CDD) at Ionia 2SSW by year
Year
Longest dry spell (CDD)
1896
18 days
1897
21 days
1898
24 days
1899
41 days
1900
30 days
1901
28 days
1902
19 days
1903
30 days
1904
13 days
1939
27 days
1942
10 days
1943
18 days
1945
15 days
1946
25 days
1947
22 days
1948
18 days
1949
18 days
1950
17 days
1951
20 days
1952
17 days
1953
23 days
1954
28 days
1955
20 days
1956
22 days
1957
22 days
1958
18 days
1959
13 days
1960
20 days
1961
23 days
1962
21 days
1963
17 days
1964
19 days
1965
15 days
1966
21 days
1967
20 days
1968
24 days
1969
28 days
1970
12 days
1971
13 days
1972
14 days
1973
14 days
1974
14 days
1975
19 days
1976
16 days
1977
17 days
1978
19 days
1979
30 days
1981
28 days
1982
22 days
1983
21 days
1984
17 days
1985
11 days
1986
21 days
1987
29 days
1988
22 days
1989
31 days
1990
18 days
1991
11 days
1992
21 days
1993
11 days
1994
24 days
1995
22 days
1996
16 days
1997
11 days
1998
14 days
1999
24 days
2000
14 days
2001
26 days
2002
26 days
2003
20 days
2004
14 days
2005
18 days
2006
19 days
2007
19 days
2008
14 days
2009
22 days
2010
17 days
2011
16 days
2012
22 days
2013
20 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
60 years with a frost
Across 60 years with a frost, the median last spring frost at Ionia 2SSW falls on 10 May and the median first autumn frost on 2 October, which leaves a median of 144 days between them.
In 1978 to 2012 the median growing season was 153 days. That is 15 days more than in 1897 to 1977.
Fitted over all years, the growing season changes by +3.2 days per decade at this station.
Frost dates and growing season at Ionia 2SSW
Measure
Median, all years
Earliest period (1897 to 1977)
Recent period (1978 to 2012)
Recent against earliest
Fitted trend
Last spring frost
10 May
13 May
4 May
9 days earlier
-1.2 days per decade
First autumn frost
2 October
27 September
7 October
10 days later
+2.0 days per decade
Growing days
144 days
138 days
153 days
15 days more
+3.2 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
64 years, 1897 to 2012
A day with at least 53.7 mm (2.1 in) of rain is expected about once in 2 years. A day with at least 107.7 mm (4.2 in) of rain is expected about once in 100 years.
Rainfall return levels at Ionia 2SSW: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
53.7 mm (2.1 in)
5 years
70.0 mm (2.8 in)
10 years
80.0 mm (3.1 in)
25 years
91.8 mm (3.6 in)
50 years
100.0 mm (3.9 in)
100 years
107.7 mm (4.2 in)
Longer than the 64 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, 64 years of values from 1897 to 2012.
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: 120.9 mm (4.8 in) in 1986; 94.5 mm (3.7 in) in 1994; 90.4 mm (3.6 in) in 1985.
Station Changes
1 suspected
One change was suspected in the annual mean temperature of Ionia 2SSW, at 1983. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1983 ran 0.3 C (0.5 F) lower than in the years before (possible change).
Suspected changes in the annual mean temperature at Ionia 2SSW, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1983
-0.3
-0.5
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 Ionia 2SSW standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Ionia 2SSW 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.