Record envelope, standing records and threshold days for Stephan 2 NW (USC00397992), South Dakota, United States, with 111 years of record.
Key Facts for Stephan 2 NW
Stephan 2 NW (USC00397992) is a weather station in South Dakota, United States at 44.27 latitude and -99.44 longitude, 550 m (1,805 ft) above sea level.
The station reports from 1903 to 2013, 111 years of record.
1,464 records set at Stephan 2 NW still stand.
Records are tracked for tmax, tmin, prcp, snow, snwd: an element needs 30 years of data to be eligible.
Stephan 2 NW set a daily record precipitation of 43.2 mm (1.7 in) on 28 May 2013.
About the Station
Location: South Dakota, United States, 44.27 latitude, -99.44 longitude.
Elevation: 550 m (1,805 ft).
Period of record: 1903 to 2013, 111 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 Stephan 2 NW. 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 Stephan 2 NW, 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)
-41.7 C (-43.1 F)
n/a
n/a
Feb
22.2 C (72.0 F)
-40.0 C (-40.0 F)
n/a
n/a
Mar
29.4 C (84.9 F)
-31.7 C (-25.1 F)
n/a
n/a
Apr
37.2 C (99.0 F)
-18.3 C (-0.9 F)
n/a
n/a
May
39.4 C (102.9 F)
-10.6 C (12.9 F)
n/a
n/a
Jun
43.3 C (109.9 F)
-1.7 C (28.9 F)
n/a
n/a
Jul
43.9 C (111.0 F)
2.2 C (36.0 F)
n/a
n/a
Aug
44.4 C (111.9 F)
-0.6 C (30.9 F)
n/a
n/a
Sep
41.7 C (107.1 F)
-9.4 C (15.1 F)
n/a
n/a
Oct
35.0 C (95.0 F)
-21.7 C (-7.1 F)
n/a
n/a
Nov
27.8 C (82.0 F)
-30.0 C (-22.0 F)
n/a
n/a
Dec
21.1 C (70.0 F)
-38.9 C (-38.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Stephan 2 NW still stand. 1985 holds the most, with 43.
Standing records at Stephan 2 NW by the year they were set
Year set
Standing records
1903
11
1904
21
1905
35
1906
23
1907
22
1908
20
1909
27
1910
35
1911
34
1912
24
1913
25
1914
35
1915
30
1916
22
1917
28
1918
9
1959
28
1960
18
1961
14
1962
30
1963
17
1964
29
1965
30
1966
24
1967
23
1968
16
1969
18
1970
15
1971
14
1972
13
1973
8
1974
25
1975
22
1976
31
1977
13
1978
18
1979
19
1980
13
1981
18
1982
11
1983
33
1984
9
1985
43
1986
19
1987
33
1988
35
1989
24
1990
17
1991
29
1992
33
1993
10
1994
22
1995
16
1996
25
1997
28
1998
22
1999
15
2000
32
2001
15
2002
22
2003
18
2004
19
2005
16
2006
17
2007
12
2008
6
2009
26
All-Time Record Progression
6 new records
6 all-time records were set at Stephan 2 NW between 2 March 1985 and 6 April 2009. Each dot is a new record.
When Stephan 2 NW set new all-time records
Date
Kind
Detail
1985-03-02
Record daily snowfall
Record daily snowfall 35.6 cm (14.0 in)
1985-03-04
Record snow depth
Record snow depth 61.0 cm (24.0 in)
1989-12-21
Record low maximum temperature
Record low maximum temperature -29.4 C (-20.9 F)
1997-01-04
Record daily snowfall
Record daily snowfall 45.7 cm (18.0 in)
2009-03-31
Record daily snowfall
Record daily snowfall 50.8 cm (20.0 in)
2009-04-06
Record snow depth
Record snow depth 63.5 cm (25.0 in)
Wettest Day of Each Month
Jul: 114.8 mm (4.5 in)
The wettest day on record for each calendar month at Stephan 2 NW. The most was 114.8 mm (4.5 in) on 26 July 1968.
Record daily precipitation for each month at Stephan 2 NW
Month
Record daily precipitation (mm)
Date
Jan
29.5 mm (1.2 in)
4 January 1997
Feb
40.1 mm (1.6 in)
18 February 1991
Mar
55.9 mm (2.2 in)
31 March 2009
Apr
52.6 mm (2.1 in)
28 April 1964
May
71.6 mm (2.8 in)
15 May 1962
Jun
76.2 mm (3.0 in)
21 June 2011
Jul
114.8 mm (4.5 in)
26 July 1968
Aug
86.4 mm (3.4 in)
30 August 1971
Sep
78.7 mm (3.1 in)
19 September 1996
Oct
57.2 mm (2.3 in)
29 October 1996
Nov
41.9 mm (1.6 in)
28 November 2005
Dec
16.5 mm (0.6 in)
26 December 1988
Period of Record Coverage
1903 to 2009
Complete yearUnder 90 percent of days
67 years of record at Stephan 2 NW, 1903 to 2009. 9 years have data for under 90 percent of days and are left out of rankings: 1903, 1918, 1959, 1963, 1968, 1972, 1973, 1999 and others.
Cooler than the station meanWarmer than the station mean
One stripe for each of 54 complete years at Stephan 2 NW, 1904 to 2007. Blue stripes are years cooler than the station's own mean of 7.1 C (44.8 F); red stripes are warmer. The coolest year was 1917, at 5.1 C (41.1 F), and the warmest was 1987, at 9.7 C (49.4 F). The strongest colour marks a difference of 2.6 C (4.7 F).
Annual mean temperature at Stephan 2 NW as warming stripes, 1904 to 2007
Year
Annual mean temperature
Difference from the station mean
1904
6.6 C
-0.54 C
1906
6.8 C
-0.28 C
1907
6.2 C
-0.87 C
1908
7.4 C
+0.31 C
1909
6.2 C
-0.88 C
1911
6.7 C
-0.36 C
1912
6.4 C
-0.75 C
1913
7.5 C
+0.35 C
1914
7.3 C
+0.24 C
1915
6.3 C
-0.81 C
1917
5.1 C
-2.03 C
1960
5.9 C
-1.23 C
1961
6.8 C
-0.26 C
1962
6.3 C
-0.77 C
1964
7.1 C
-0.04 C
1965
6.3 C
-0.81 C
1966
6.1 C
-0.96 C
1967
6.6 C
-0.53 C
1969
6.6 C
-0.47 C
1970
6.6 C
-0.49 C
1971
6.8 C
-0.26 C
1974
8.4 C
+1.25 C
1975
7.4 C
+0.29 C
1976
8.4 C
+1.33 C
1977
7.7 C
+0.62 C
1978
5.8 C
-1.30 C
1979
6.2 C
-0.89 C
1980
8.0 C
+0.94 C
1981
8.5 C
+1.39 C
1982
5.7 C
-1.36 C
1983
7.0 C
-0.14 C
1984
7.2 C
+0.09 C
1985
5.3 C
-1.76 C
1986
7.7 C
+0.59 C
1987
9.7 C
+2.55 C
1988
8.3 C
+1.20 C
1989
7.1 C
-0.02 C
1990
8.6 C
+1.51 C
1991
8.5 C
+1.36 C
1992
7.7 C
+0.61 C
1993
6.2 C
-0.93 C
1994
7.4 C
+0.25 C
1995
7.3 C
+0.18 C
1996
5.5 C
-1.65 C
1997
7.1 C
-0.02 C
1998
8.8 C
+1.74 C
2000
7.4 C
+0.27 C
2001
7.3 C
+0.15 C
2002
7.3 C
+0.19 C
2003
7.3 C
+0.15 C
2004
7.3 C
+0.17 C
2005
8.1 C
+0.95 C
2006
8.4 C
+1.31 C
2007
7.5 C
+0.36 C
The annual mean temperature here has risen by 0.11 C (0.03 to 0.18) per decade over 1904 to 2007. In Fahrenheit: 0.2 F (0.1 to 0.3) per decade. The slope is a straight line fitted to 54 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Stephan 2 NW
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.11 C (0.03 to 0.18) per decade
0.2 F (0.1 to 0.3) per decade
1904 to 2007
54
Rise
Mean daily maximum
0.08 C (-0.01 to 0.17) per decade
0.14 F (-0.02 to 0.30) per decade
1904 to 2007
54
Not clearly different from zero
Mean daily minimum
0.14 C (0.04 to 0.23) per decade
0.2 F (0.1 to 0.4) per decade
1904 to 2007
54
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
1903 to 2013
Yearly extremes at Stephan 2 NW: 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)
1965
39.4 C (102.9 F)
67
Coldest night (TNn)
-41.7 C (-43.1 F)
1912
-32.2 C (-26.0 F)
67
Wettest day (Rx1day)
114.8 mm (4.5 in)
1968
43.2 mm (1.7 in)
73
Wettest five days (Rx5day)
131.3 mm (5.2 in)
1968
65.0 mm (2.6 in)
73
Longest dry spell (CDD)
93 days
1964
37 days
73
Hottest day (TXx)
The hottest day of the year at Stephan 2 NW, 1903 to 2013. The record is 44.4 C (111.9 F) in 1965, marked on the chart; the median year is 39.4 C (102.9 F).
Hottest day (TXx) at Stephan 2 NW by year
Year
Hottest day (TXx)
1903
35.0 C (95.0 F)
1904
39.4 C (102.9 F)
1905
40.0 C (104.0 F)
1906
36.7 C (98.1 F)
1907
37.8 C (100.0 F)
1908
37.8 C (100.0 F)
1909
39.4 C (102.9 F)
1910
38.3 C (100.9 F)
1911
40.0 C (104.0 F)
1912
40.0 C (104.0 F)
1913
39.4 C (102.9 F)
1914
39.4 C (102.9 F)
1915
34.4 C (93.9 F)
1916
38.9 C (102.0 F)
1917
40.6 C (105.1 F)
1918
31.7 C (89.1 F)
1948
n/a
1950
n/a
1951
n/a
1959
41.1 C (106.0 F)
1960
38.9 C (102.0 F)
1961
38.9 C (102.0 F)
1962
40.0 C (104.0 F)
1963
41.1 C (106.0 F)
1964
40.6 C (105.1 F)
1965
44.4 C (111.9 F)
1966
42.8 C (109.0 F)
1967
38.9 C (102.0 F)
1968
38.3 C (100.9 F)
1969
39.4 C (102.9 F)
1970
38.9 C (102.0 F)
1971
40.0 C (104.0 F)
1972
37.2 C (99.0 F)
1973
41.1 C (106.0 F)
1974
41.1 C (106.0 F)
1975
41.7 C (107.1 F)
1976
43.9 C (111.0 F)
1977
38.3 C (100.9 F)
1978
41.1 C (106.0 F)
1979
40.6 C (105.1 F)
1980
43.9 C (111.0 F)
1981
39.4 C (102.9 F)
1982
37.8 C (100.0 F)
1983
41.7 C (107.1 F)
1984
38.9 C (102.0 F)
1985
42.8 C (109.0 F)
1986
38.9 C (102.0 F)
1987
41.1 C (106.0 F)
1988
43.9 C (111.0 F)
1989
41.7 C (107.1 F)
1990
37.8 C (100.0 F)
1991
41.7 C (107.1 F)
1992
36.1 C (97.0 F)
1993
35.6 C (96.1 F)
1994
37.8 C (100.0 F)
1995
37.8 C (100.0 F)
1996
36.7 C (98.1 F)
1997
35.6 C (96.1 F)
1998
37.8 C (100.0 F)
1999
40.0 C (104.0 F)
2000
41.1 C (106.0 F)
2001
39.4 C (102.9 F)
2002
41.1 C (106.0 F)
2003
41.7 C (107.1 F)
2004
36.7 C (98.1 F)
2005
42.2 C (108.0 F)
2006
43.9 C (111.0 F)
2007
40.6 C (105.1 F)
2008
36.1 C (97.0 F)
2009
36.7 C (98.1 F)
2011
n/a
2012
n/a
2013
n/a
Coldest night (TNn)
The coldest night of the year at Stephan 2 NW, 1903 to 2013. The record is -41.7 C (-43.1 F) in 1912, marked on the chart; the median year is -32.2 C (-26.0 F).
Coldest night (TNn) at Stephan 2 NW by year
Year
Coldest night (TNn)
1903
-32.8 C (-27.0 F)
1904
-32.2 C (-26.0 F)
1905
-39.4 C (-38.9 F)
1906
-34.4 C (-29.9 F)
1907
-30.0 C (-22.0 F)
1908
-29.4 C (-20.9 F)
1909
-31.7 C (-25.1 F)
1910
-30.6 C (-23.1 F)
1911
-36.7 C (-34.1 F)
1912
-41.7 C (-43.1 F)
1913
-34.4 C (-29.9 F)
1914
-37.2 C (-35.0 F)
1915
-32.2 C (-26.0 F)
1916
-37.2 C (-35.0 F)
1917
-38.9 C (-38.0 F)
1918
-38.3 C (-36.9 F)
1948
n/a
1950
n/a
1951
n/a
1959
-30.0 C (-22.0 F)
1960
-33.3 C (-27.9 F)
1961
-33.3 C (-27.9 F)
1962
-34.4 C (-29.9 F)
1963
-33.9 C (-29.0 F)
1964
-30.0 C (-22.0 F)
1965
-32.2 C (-26.0 F)
1966
-35.6 C (-32.1 F)
1967
-32.8 C (-27.0 F)
1968
-32.2 C (-26.0 F)
1969
-28.3 C (-18.9 F)
1970
-36.7 C (-34.1 F)
1971
-31.7 C (-25.1 F)
1972
-35.0 C (-31.0 F)
1973
-30.0 C (-22.0 F)
1974
-31.7 C (-25.1 F)
1975
-30.6 C (-23.1 F)
1976
-30.0 C (-22.0 F)
1977
-32.2 C (-26.0 F)
1978
-32.2 C (-26.0 F)
1979
-31.7 C (-25.1 F)
1980
-30.0 C (-22.0 F)
1981
-32.2 C (-26.0 F)
1982
-37.8 C (-36.0 F)
1983
-35.6 C (-32.1 F)
1984
-33.9 C (-29.0 F)
1985
-33.3 C (-27.9 F)
1986
-28.9 C (-20.0 F)
1987
-23.3 C (-9.9 F)
1988
-33.9 C (-29.0 F)
1989
-33.9 C (-29.0 F)
1990
-35.6 C (-32.1 F)
1991
-27.2 C (-17.0 F)
1992
-25.0 C (-13.0 F)
1993
-28.3 C (-18.9 F)
1994
-40.0 C (-40.0 F)
1995
-26.1 C (-15.0 F)
1996
-37.8 C (-36.0 F)
1997
-29.4 C (-20.9 F)
1998
-31.1 C (-24.0 F)
1999
-29.4 C (-20.9 F)
2000
-31.1 C (-24.0 F)
2001
-27.2 C (-17.0 F)
2002
-23.9 C (-11.0 F)
2003
-30.0 C (-22.0 F)
2004
-27.8 C (-18.0 F)
2005
-30.6 C (-23.1 F)
2006
-26.1 C (-15.0 F)
2007
-29.4 C (-20.9 F)
2008
-30.0 C (-22.0 F)
2009
-33.3 C (-27.9 F)
2011
n/a
2012
n/a
2013
n/a
Wettest day (Rx1day)
The wettest day of the year at Stephan 2 NW, 1903 to 2013. The record is 114.8 mm (4.5 in) in 1968, marked on the chart; the median year is 43.2 mm (1.7 in).
Wettest day (Rx1day) at Stephan 2 NW by year
Year
Wettest day (Rx1day)
1903
16.0 mm (0.6 in)
1904
69.9 mm (2.8 in)
1905
50.3 mm (2.0 in)
1906
76.2 mm (3.0 in)
1907
51.8 mm (2.0 in)
1908
48.8 mm (1.9 in)
1909
51.6 mm (2.0 in)
1910
25.4 mm (1.0 in)
1911
66.5 mm (2.6 in)
1912
33.0 mm (1.3 in)
1913
32.0 mm (1.3 in)
1914
66.0 mm (2.6 in)
1915
38.4 mm (1.5 in)
1916
51.6 mm (2.0 in)
1917
40.6 mm (1.6 in)
1918
38.1 mm (1.5 in)
1948
44.5 mm (1.8 in)
1950
71.4 mm (2.8 in)
1951
40.6 mm (1.6 in)
1959
30.7 mm (1.2 in)
1960
40.6 mm (1.6 in)
1961
69.9 mm (2.8 in)
1962
71.6 mm (2.8 in)
1963
29.2 mm (1.1 in)
1964
52.6 mm (2.1 in)
1965
38.1 mm (1.5 in)
1966
36.8 mm (1.4 in)
1967
45.7 mm (1.8 in)
1968
114.8 mm (4.5 in)
1969
38.1 mm (1.5 in)
1970
27.9 mm (1.1 in)
1971
86.4 mm (3.4 in)
1972
40.6 mm (1.6 in)
1973
33.5 mm (1.3 in)
1974
39.6 mm (1.6 in)
1975
41.9 mm (1.6 in)
1976
41.4 mm (1.6 in)
1977
43.2 mm (1.7 in)
1978
73.7 mm (2.9 in)
1979
39.4 mm (1.6 in)
1980
42.4 mm (1.7 in)
1981
83.8 mm (3.3 in)
1982
40.1 mm (1.6 in)
1983
50.8 mm (2.0 in)
1984
29.5 mm (1.2 in)
1985
53.8 mm (2.1 in)
1986
41.1 mm (1.6 in)
1987
23.9 mm (0.9 in)
1988
38.6 mm (1.5 in)
1989
50.8 mm (2.0 in)
1990
40.6 mm (1.6 in)
1991
45.0 mm (1.8 in)
1992
44.5 mm (1.8 in)
1993
38.1 mm (1.5 in)
1994
48.0 mm (1.9 in)
1995
48.3 mm (1.9 in)
1996
78.7 mm (3.1 in)
1997
51.1 mm (2.0 in)
1998
56.4 mm (2.2 in)
1999
64.5 mm (2.5 in)
2000
29.7 mm (1.2 in)
2001
29.7 mm (1.2 in)
2002
51.8 mm (2.0 in)
2003
66.3 mm (2.6 in)
2004
45.0 mm (1.8 in)
2005
41.9 mm (1.6 in)
2006
34.8 mm (1.4 in)
2007
51.8 mm (2.0 in)
2008
40.6 mm (1.6 in)
2009
55.9 mm (2.2 in)
2011
76.2 mm (3.0 in)
2012
28.4 mm (1.1 in)
2013
43.2 mm (1.7 in)
Wettest five days (Rx5day)
The wettest five days of the year at Stephan 2 NW, 1903 to 2013. The record is 131.3 mm (5.2 in) in 1968, marked on the chart; the median year is 65.0 mm (2.6 in).
Wettest five days (Rx5day) at Stephan 2 NW by year
Year
Wettest five days (Rx5day)
1903
28.1 mm (1.1 in)
1904
84.6 mm (3.3 in)
1905
67.8 mm (2.7 in)
1906
125.2 mm (4.9 in)
1907
88.7 mm (3.5 in)
1908
61.7 mm (2.4 in)
1909
74.2 mm (2.9 in)
1910
49.8 mm (2.0 in)
1911
97.5 mm (3.8 in)
1912
56.9 mm (2.2 in)
1913
49.0 mm (1.9 in)
1914
97.5 mm (3.8 in)
1915
112.6 mm (4.4 in)
1916
61.3 mm (2.4 in)
1917
40.6 mm (1.6 in)
1918
74.6 mm (2.9 in)
1948
77.3 mm (3.0 in)
1950
87.1 mm (3.4 in)
1951
61.7 mm (2.4 in)
1959
56.2 mm (2.2 in)
1960
45.3 mm (1.8 in)
1961
83.3 mm (3.3 in)
1962
99.5 mm (3.9 in)
1963
60.0 mm (2.4 in)
1964
94.5 mm (3.7 in)
1965
47.0 mm (1.9 in)
1966
55.9 mm (2.2 in)
1967
72.6 mm (2.9 in)
1968
131.3 mm (5.2 in)
1969
40.1 mm (1.6 in)
1970
42.3 mm (1.7 in)
1971
92.8 mm (3.7 in)
1972
41.4 mm (1.6 in)
1973
46.7 mm (1.8 in)
1974
59.9 mm (2.4 in)
1975
72.4 mm (2.9 in)
1976
41.4 mm (1.6 in)
1977
57.2 mm (2.3 in)
1978
73.7 mm (2.9 in)
1979
42.0 mm (1.7 in)
1980
58.9 mm (2.3 in)
1981
86.3 mm (3.4 in)
1982
82.4 mm (3.2 in)
1983
62.0 mm (2.4 in)
1984
52.9 mm (2.1 in)
1985
72.9 mm (2.9 in)
1986
55.4 mm (2.2 in)
1987
44.7 mm (1.8 in)
1988
81.0 mm (3.2 in)
1989
57.1 mm (2.2 in)
1990
57.1 mm (2.2 in)
1991
76.2 mm (3.0 in)
1992
88.7 mm (3.5 in)
1993
67.9 mm (2.7 in)
1994
48.0 mm (1.9 in)
1995
66.5 mm (2.6 in)
1996
123.4 mm (4.9 in)
1997
53.9 mm (2.1 in)
1998
81.8 mm (3.2 in)
1999
109.2 mm (4.3 in)
2000
32.6 mm (1.3 in)
2001
63.8 mm (2.5 in)
2002
64.7 mm (2.5 in)
2003
102.0 mm (4.0 in)
2004
65.8 mm (2.6 in)
2005
83.1 mm (3.3 in)
2006
43.7 mm (1.7 in)
2007
71.9 mm (2.8 in)
2008
65.0 mm (2.6 in)
2009
61.8 mm (2.4 in)
2011
107.9 mm (4.2 in)
2012
71.4 mm (2.8 in)
2013
63.3 mm (2.5 in)
Longest dry spell (CDD)
The longest dry spell of the year at Stephan 2 NW, 1903 to 2013. The record is 93 days in 1964, marked on the chart; the median year is 37 days.
Longest dry spell (CDD) at Stephan 2 NW by year
Year
Longest dry spell (CDD)
1903
36 days
1904
67 days
1905
32 days
1906
22 days
1907
60 days
1908
30 days
1909
48 days
1910
35 days
1911
37 days
1912
54 days
1913
52 days
1914
44 days
1915
40 days
1916
52 days
1917
69 days
1918
24 days
1948
38 days
1950
25 days
1951
21 days
1959
28 days
1960
30 days
1961
36 days
1962
38 days
1963
29 days
1964
93 days
1965
30 days
1966
33 days
1967
71 days
1968
78 days
1969
23 days
1970
30 days
1971
32 days
1972
28 days
1973
20 days
1974
50 days
1975
37 days
1976
34 days
1977
26 days
1978
43 days
1979
55 days
1980
53 days
1981
86 days
1982
44 days
1983
63 days
1984
42 days
1985
25 days
1986
42 days
1987
45 days
1988
39 days
1989
24 days
1990
45 days
1991
38 days
1992
39 days
1993
27 days
1994
30 days
1995
34 days
1996
24 days
1997
27 days
1998
48 days
1999
44 days
2000
43 days
2001
30 days
2002
33 days
2003
18 days
2004
21 days
2005
31 days
2006
47 days
2007
40 days
2008
17 days
2009
38 days
2011
25 days
2012
44 days
2013
27 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
54 years with a frost
Across 54 years with a frost, the median last spring frost at Stephan 2 NW falls on 14 May and the median first autumn frost on 21 September, which leaves a median of 129 days between them.
Fitted over all years, the growing season changes by +0.2 days per decade at this station.
Frost dates and growing season at Stephan 2 NW
Measure
Median, all years
Earliest period
Recent period (1977 to 2007)
Recent against earliest
Fitted trend
Last spring frost
14 May
n/a
14 May
n/a
-0.3 days per decade
First autumn frost
21 September
n/a
21 September
n/a
-0.1 days per decade
Growing days
129 days
n/a
133 days
n/a
+0.2 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
58 years, 1904 to 2012
A day with at least 45.5 mm (1.8 in) of rain is expected about once in 2 years. A day with at least 96.2 mm (3.8 in) of rain is expected about once in 100 years.
Rainfall return levels at Stephan 2 NW: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
45.5 mm (1.8 in)
5 years
59.1 mm (2.3 in)
10 years
68.1 mm (2.7 in)
25 years
79.4 mm (3.1 in)
50 years
87.8 mm (3.5 in)
100 years
96.2 mm (3.8 in)
Longer than the 58 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, 58 years of values from 1904 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: 86.4 mm (3.4 in) in 1971; 83.8 mm (3.3 in) in 1981; 78.7 mm (3.1 in) in 1996.
Station Changes
2 suspected
2 changes were suspected in the annual mean temperature of Stephan 2 NW, at 1987 and 2000. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1987 ran 0.3 C (0.5 F) higher than in the years before (possible change).
Relative to 5 neighbouring stations, the station's annual mean temperature from 2000 ran 0.6 C (1.0 F) lower than in the years before (possible change).
Suspected changes in the annual mean temperature at Stephan 2 NW, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1987
+0.3
+0.5
possible
5
2000
-0.6
-1.0
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 Stephan 2 NW standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Stephan 2 NW 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 2026-10-13 (13 October 2026). Records are computed by this site and are not official.